Abstract:
A photoluminescent member is provided for an exit device. The photoluminescent member comprises a housing member for mounting to the exterior surface of the exit device. The housing member includes a photoluminescent portion for being energized by exposure to an ambient light source and operable to automatically emit visible light photoluminescently for a substantial period of time in low ambient light or dark conditions and without being energized by an electrical current so that the photoluminescent portion provides illumination to identify the exit device in the low ambient light or dark conditions for providing a visual cue directing a person to a location of the exit device.

Description:
BACKGROUND 
     The present invention relates to exit devices, and more particularly to exit devices that are visible in low light or dark conditions. 
     An exit device is a manual or electronic door operating mechanism operated from the inside of a door. A conventional exit device generally includes a frame or housing secured across a door face and substantially spanning the width of the door. A touch bar is movably mounted to the frame. The touch bar is mechanically linked to a latch mechanism, including a door latch which is movably mounted in the frame adjacent to a free edge of the door. Manually depressing the touch bar in the frame toward the door translates the mechanical linkage for actuating the latch mechanism in order to retract the door latch so that the door can be opened allowing egress. 
     During low light or dark conditions, such as during a power failure, or in an emergency, it is important to those within the building to quickly identify building exit doors. Commercial buildings are required to have signs identifying exits as well as directional or warning signage, which indicate to building occupants a path for leaving the building in low light or dark conditions. A pathway marking system may include passive lighting, which does not require a power source, to demarcate the outlines or sections of buildings structures such as stair risers, intersections of walls and floor, sloped ramps, doorways, hallways, or the location of handrails, and the like. Some passive pathway marking systems utilize photoluminescent materials which provide low level light as they discharge their stored energy. Photoluminescent materials contain inorganic phosphorus and pigments that absorb ambient light. In darkness, the photoluminescent material produces a sustained visible yellow-green, red or blue glow which provides sufficient illumination for guiding someone out of a darkened area. Examples of photoluminescent materials include zinc sulfide and alkaline metal oxide aluminates, such as calcium sulfide and strontium sulfide. 
     Unfortunately, passive marking systems have not been applied to exit devices. Electroluminescent exit devices are available. However, an electroluminescent exit device requires electricity with battery back-up power, and includes electrical wiring which extends through the exit device, the door and one of the door hinges for connection to a source of power. 
     For the foregoing reasons, there is a need for a photoluminescent exit device which is visible in low light or dark conditions for directing an occupant to a point of egress of a room or a building. The new exit device should ideally function effectively as a passive lighting device in a pathway marking 
     SUMMARY 
     According to the present invention, a photoluminescent member is provided for an exit device, the photoluminescent member comprising a housing member for mounting to the exterior surface of the exit device, the housing member including a photoluminescent portion for being energized by exposure to an ambient light source and operable to automatically emit visible light photoluminescently for a substantial period of time in low ambient light or dark conditions and without being energized by an electrical current so that the photoluminescent portion provides illumination to identify the exit device in the low ambient light or dark conditions for providing a visual cue directing a person to a location of the exit device. 
     Also according to the present invention, an exit device is provided comprising a frame for attachment to a surface of the door, a door latch mechanism mounted to the frame, the door latch mechanism including a latch bolt movable relative to the frame from an extended position to a retracted position. Means for actuating the exit device are movably mounted to the frame and operatively connected to the latch mechanism for moving the latch bolt from the extended position to the retracted position when pressure is applied to the actuating means for opening the door. A photoluminescent member is mounted to the frame, the photoluminescent member including a portion for being energized by exposure to an ambient light source and operable to automatically emit visible light photoluminescently for a substantial period of time in low ambient light or dark conditions and without being energized by an electrical current so that the photoluminescent member provides illumination to identify the exit device in the low ambient light or dark conditions for providing a visual cue directing a person to a location of the exit device. 
     Further according to the present invention, a combination including a door pivotally mounted along one edge to a door frame and an exit device is provided. The exit device comprises a housing adapted to be secured to the door surface and a latch bolt disposed at one end of the housing adjacent an edge of the door and movable relative to the housing between a projected position extending outwardly of the housing for securing the door relative to the frame in a closed position and a retracted position where the latch bolt is inside the housing for allowing the door to be opened. An actuator is movably supported on the housing for movement relative to the housing from a first position to a second position and operatively connected to the latch mechanism for moving the latch from the extended position to the retracted position when pressure is applied to the actuator for opening the door in response to movement of the actuator toward the second position of the actuator. A photoluminescent member is disposed on the housing, the photoluminescent member being energized by exposure to an ambient light source and operable to automatically emit visible light photoluminescently for a substantial period of time in low ambient light or dark conditions and without being energized by an electrical current. The photoluminescent member provides illumination to identify the exit device in the low ambient light or dark conditions for providing a visual cue directing a person to a location of the exit device and the door. 
     Still further according to the present invention, a system is provided for indicating the direction of an exit route for use in a building including a door through which a person will move in following the exit route. The system comprises a door pivotally mounted along one edge to a door frame and an exit device. The exit device comprises a housing adapted to be secured to the door surface and a latch bolt disposed at one end of the housing adjacent an edge of the door and movable relative to the housing between a projected position extending outwardly of the housing for securing the door relative to the frame in a closed position and a retracted position where the latch bolt is inside the housing for allowing the door to be opened. An actuator is movably supported on the housing for movement relative to the housing form a first position to a second position and operatively connected to the latch mechanism for moving the latch from the extended position to the retracted position when pressure is applied to the actuating means is pushed for opening the door in response to movement of the actuator member toward the second position of the actuator member. A photoluminescent member is disposed on the housing, the photoluminescent member being energized by exposure to an ambient light source and operable to automatically emit visible light photoluminescently for a substantial period of time in low ambient light or dark conditions and without being energized by an electrical current. The photoluminescent member provides illumination to identify the exit device in the low ambient light or dark conditions for providing a visual cue directing a person to a location of the exit device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present invention, reference should now be had to the embodiments shown in the accompanying drawings and described below. In the drawings: 
         FIG. 1  is a perspective view of an exit device according to the present invention mounted on a door; 
         FIG. 2  is an exploded perspective view of the exit device shown in  FIG. 1  with a latch cover, end plate and touch bar removed; 
         FIG. 3  is a longitudinal cross section of the touch bar shown in  FIG. 2 ; and 
         FIG. 4  is a front elevation view of a touch bar with the word “EXIT” for use with the exit device according to the present invention. 
     
    
    
     DESCRIPTION 
     The present invention provides a photoluminescent exit device that is visible in low light or dark conditions. The exit device according to the present invention is for use in commercial applications and the photoluminescent feature may be adapted for use with any conventional exit device such as, for example, the exit devices described by U.S. Pat. No. 4,796,931; U.S. Pat. No. 5,042,851; U.S. Pat. No. 5,605,362 and U.S. Pat. No. 5,816,017, the contents of all of which are hereby incorporated by reference. Accordingly, detailed explanations of the functioning of all of the exit device components are deemed unnecessary for understanding the present invention by one of ordinary skill in the art. 
     Certain terminology is used herein for convenience only and is not to be taken as a limitation on the invention. For example, words such as “upper,” “lower,” “left,” “right,” “horizontal,” “vertical,” “upward,” and “downward” merely describe the configuration shown in the FIGs. Indeed, the components may be oriented in any direction and the terminology, therefore, should be understood as encompassing such variations unless specified otherwise. 
     Referring now to the drawings, wherein like reference numerals designate corresponding or similar elements throughout several views,  FIG. 1  shows an exit device according to the present invention mounted to a door to be secured and generally designated at  10 . The exit device  10  includes an elongated frame  12  that is mounted at a horizontal position across the interior surface of the door  14 . The housing  12  comprises a touch bar  16 , a latch housing  18  at one end and a cover plate  20  having an end cap  22  at the other end. The touch bar  16  longitudinally spans a substantial portion of the housing  12  and defines a surface  24  for receiving a manual pushing force exerted toward the door  14  by a person attempting to egress through the door. 
     According to the present invention, at least a portion of the exit device  10  includes photoluminescent material which provides a light source in low light or dark conditions. In one embodiment of the present invention, the portion of the exit device  10  that comprises photoluminescent material is the touch bar  16 . 
     Referring to  FIG. 2 , the latch housing  18 , touch bar  16 , and a front end cap  26  are shown separate from the remaining components of the exit device  10 . A door latch mechanism  28  and an actuator  30  are visible. The latch mechanism  28  may be of the type illustrated, or it may be a concealed or visible vertical rod type, or any other type of latch mechanism known in the art. The actuator  30  is movably mounted in the frame  12  and operably connected to the latch mechanism  28 . When manual pushing force is applied to the actuator  30  through the touch bar  16 , the latch mechanism  28  is operated allowing opening of the door  14 . It is understood that the actuator  30  may be a pushbar, push rail, push plate or other type of exit device actuator known in the art. 
     Referring to  FIG. 3 , the touch bar  16  comprises a solid, generally C-shaped body having a front surface  32  and a back surface  34 . The body of the touch bar  16  terminates in opposed in-turned flanges  36  which cooperate to define a receiving track. The cross-section of the touch bar  16  is designed to correspond to the cross-section of the actuator  30  and the receiving track is dimensioned for receiving the upper and lower edges of the actuator  30 . With this configuration, when the latch housing  18  and the front end cap  26  removed ( FIG. 2 ), the touch bar  16  may be slipped lengthwise over the actuator  30  for releasably coupling the touch bar  16  to the actuator  30  and the exit device  10  structure. It is understood that such removable attachment of the touch bar  16  to the exit device  10  simplifies repair and allows retrofit of the photoluminescent touch bar  16  to an exit device which has a conventional touch bar. 
     In the one embodiment of the present invention, the front surface  32  of the touch bar  16  includes a photoluminescent material. The photoluminescent material can be applied to the front surface  32  of the touch bar  16  using a coating composition which includes a photoluminescent pigment. A suitable photoluminescent material is available from Luna Technologies International, Inc., of Kent, Wash., sold under the trade name LUNAplast™, and comprises a strontium aluminate formulation. This strontium aluminate formulation is described in published international patent application number WO 99/27294, entitled “Photoluminescent Light Emitter with Enhanced Photometric Brightness Characteristics,” published Jun. 3, 1999, the contents of which are hereby incorporated by reference. In a preferred embodiment, a stainless steel touch bar  16  is first cleaned and coated with a white epoxy enamel paint. After curing, the touch bar  16  is then coated with a proprietary powder product. The powder product is a TGIC polyester specially blended powder material. The touch bar  16  is then cured. 
     It is understood that many alternatives are available for rendering photoluminescence to the touch bar  16 , or any other component of the exit device  10 . For example, photoluminescent material is commercially available as an acrylic water-based paint, a tape, and in vinyl strips for application on a substrate. In addition, commercially available phosphorescent powders can be mixed with a suitable carrier to produce a paste that can be applied to the substrate. The tape or a strip of photoluminescent material may be affixed to the front surface  32  of the touch bar  16  with an adhesive such that the photoluminescent material overlays the touch bar  16 . Moreover, although the strontium aluminate is described above as a preferred photoluminescent material, zinc sulfide or other alkaline metal oxide aluminate-based photoluminescent material can also be used. In addition, it is understood that many alternatives for rendering photoluminescence to the exit device  10 , or any component of the exit device. The touch bar  16  is preferred, but is only one example. The most important feature is that the photoluminescent component provides visibility to an occupant of a building. 
     Alternatively, a photoluminescent material may be mixed with a formable structural material for producing a unitary product used a component of an exit device  10 , such as the touch bar  16 . In this embodiment, the touch bar  16  can be manufactured by an extrusion or molding process from rubber, vinyl, and the like, to name a few suitable materials. A hard, durable plastic is another example, such as an acrylic plastic or a polyethylene plastic. The selected material should be impact resistant. Other selection criteria for the material include expected life, cost and suitability for use as a component of an exit device. Photoluminescent dyes or particles of a photoluminescent material may be dispensed in the structural material prior to forming. Because the composition has been formed together, the photoluminescent material is spread throughout the depth of the touch bar  16  and the glow is emitted by the photoluminescent dye or particles within the body of the touch bar. 
     An exit device  10  with a photoluminescent touch bar  16  according to the present invention is visible in low light or dark conditions. The photoluminescent exit device  10  emits light for an appreciable time allowing an occupant to locate the exit device  10  and door  14 . The building occupant is thus directed to the exit device  10  by the glow of the touch bar  16 . Moreover, the touch bar  16  also provides a visual directional cue, signaling the location of the door and exit device  10  and the location of the actuator  30  for the exit device  10 . When the building occupant room needs to exit the building, the occupant applies pressure to the illuminated touch bar  16  thereby opening the door  14  for egress. Further, the exit device  10  may function as a part of an emergency egress indication system including the exit device  10 , signage, directional indicator stripes, doorway markings, stairway and lighting indication and the like. 
     A graphic, such as a sign or display may be included on the front surface  32  of the touch bar  16 . As shown in  FIG. 4 , the word “EXIT” is mounted directly on the touch bar  16 . Other words, such as “EMERGENCY” or “EMERGENCY EXIT”, or symbols may be employed, such as an arrow or other indicia (not shown). The sign can be applied using an opaque material laid over the photoluminescent material, such as an opaque film adhesively attached to the touch bar  16  thereby masking out the emitted light. An opaque paint or dye may also be applied to the touch bar. This leaves essentially dark marking portions for blocking illumination from the light emitting background. Alternatively, the touch bar or other background can be blacked out, letting the sign glow in the dark. The opaque portions may form the lettering of the sign or the area around the lettering. Alternatively, dyes, stains, and inks can be applied over the photoluminescent material. The dyes, stains, or inks glow in the dark with a different color than that of the photoluminescent layer. Thus, the both the background and the markings emit light. The sign and photoluminescent background form a sign assembly visibly mounted on the exit device. 
     Other alternatives are possible in keeping with the present invention. For example, a layer of reflective material may be provided on top of the photoluminescent portion of the exit device. The reflective material will also act as a light source and also reflect light. Preferably, the layer of reflective material is transparent in addition to being reflective. This will allow light emitted from the photoluminescent material to pass through the reflective layer. 
     Although the present invention has been shown and described in considerable detail with respect to only a few exemplary embodiments thereof, it should be understood by those skilled in the art that we do not intend to limit the invention to the embodiments since various modifications, omissions and additions may be made to the disclosed embodiments without materially departing from the novel teachings and advantages of the invention, particularly in light of the foregoing teachings. For example, any component of the exterior of the exit device could be rendered photoluminescent. Accordingly, we intend to cover all such modifications, omissions, additions and equivalents as may be included within the spirit and scope of the invention as defined by the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures.