Abstract:
An air handling luminaire having a light diffuser, louver, or lamp shield made of a flammable material and mounted within a luminaire housing. Integral with the luminaire housing is a heat distortable support clip from which the light diffuser, louver, or lamp shield depends. The luminaire housing also has a ballast channel and at least one reflector mounted therein. The ballast channel and luminaire housing have a plurality of vents and air gaps for fluid communication with an air plenum. The heat distortable support clip non-permanently deforms or distorts when introduced to a predetermined temperature in order to release the lamp shield from the housing and prevent burning thereof.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field of the Invention 
     The present invention relates to a support for a lamp shield having a flammable component for an air handling luminaire. More particularly, the present invention relates to a heat distortable (without melting) support, which extends away from a lamp shield and removes support, during high temperature conditions so that a lamp shield or louver having a flammable component does not burn in an air handling plenum allowing the fire to spread, in compliance with Standard for Safety UL1598, Paragraphs 9.2.3.2, and 9.2.3.3. 
     2. Description of the Related Art 
     Heat transfer luminaires, also known as air handling luminaires, add or remove heat from an area by moving air therethrough. Metal louvers or lamp shields are currently used because they are durable and generally do not catch fire. It is preferable to have a plastic inlay or film within the lamp shields to more accurately direct light and provide desired lighting characteristics. However, since the plastic inlay is flammable it may catch fire and, due to the metal lamp shield beneath, the inlay cannot fall. If the plastic inlay or film catches fire, its close proximity to the air handling system makes likely the spread of fire or fumes through the air handling system which does not does not comply with commercial fire codes. 
     In view of the deficiencies of known air handling luminaires it is apparent that an air handling luminaire is needed having a metal lamp shield and a plastic inlay which may be released from the air handling luminaire during fire conditions, thus inhibiting the spread of fire through air handling systems. 
     SUMMARY OF THE INVENTION 
     It is an objective of this invention to provide a laminated support clip for use with a luminaire. 
     It is yet an even further objective of the present invention to provide a laminated support clip for a flammable portion of a lamp shield on a luminaire wherein the support clip distorts at a predefined temperature and removes support from the flammable portion of the lamp shield. 
     It is still an even further objective of the present invention to provide a laminated support clip for a flammable portion of a lamp shield on a luminaire wherein the support clip distorts at a predefined temperature and thus removes support from the flammable portion of the lamp shield and wherein the luminaire may be connected to an air handling plenum for removing air from an area, room, or the like. 
     An air handling luminaire, comprising a luminaire housing having a top wall and four sidewalls depending therefrom, a light diffuser or lamp shield operably mounted adjacent to the luminaire housing, at least one support clip having a first leg connected to the luminaire body and a second leg supporting the lamp shield. The air handling luminaire support clip is comprised of laminated dissimilar metals and is substantially L-shaped. The support clip has a first long leg and a second short leg. The second leg of the at least one support clip is positioned through the luminaire housing to support the lamp shield. The at least one support clip is connected to the luminaire housing through a hole in the first leg of the at least one support clip. 
     The lamp shield is preferably formed of both flammable and non-flammable materials. More specifically the lamp shield is metallic having a plastic film on an inner side thereof. Additionally, the lamp shield is preferably concave shaped and flexible. 
     The luminaire housing is comprised of a top wall and at least one sidewall. At least one reflector is connected between a ballast channel and the luminaire housing. The ballast channel and the top wall preferably have vents for fluid communication with an air handling plenum. The vents are preferably in fluid communication with an air gap. The air gap is formed by the luminaire housing, the at least one reflector, and a ballast channel. 
     All of the above outlined objectives are to be understood as exemplary only and many more objectives of the invention may be gleaned from the disclosure herein. Therefore, no limiting interpretation of the objectives noted are to be understood without further reading of the entire specification, claims, and drawings included herewith. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The aspects and advantages of the present invention will be better understood when the detailed description of the preferred embodiment is taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 shows an assembly drawing of the Air Handling Luminaire of the present invention; 
     FIG. 2 shows a side view of the Air Handling Luminaire of the present invention of FIG. 1; and, 
     FIG. 3 shows a dissimilar metal support clip of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 and 2, an air handling luminaire  10  is shown having a luminaire housing or body  12 , a lamp shield, light diffuser, or louver  14 , and a support clip  30 . The support clip  30  provides a means to support the diffuser from the luminaire housing  12  as will be discussed below. The luminaire housing  12  can be of various sizes and shapes required for ceilings in, for example, a commercial building. For instance, in typical commercial buildings, drop or suspended ceilings may be grid like in construction having acoustically absorbent ceiling tiles separated and supported by metal or plastic t-grid  24 . The t-grid  24  may alternatively be exposed slot t-grid while the tiles supported by the t-grid  24  may be square or rectangular in shape. 
     The air handling luminaire  10  may be sized to match the ceiling tile size and provide an improved aesthetic appearance. Each air handling luminaire  10  is located in a ceiling space provided in the grid and is preferably of a size equal to a single ceiling tile, as will be understood by one of skill in the art. The air handling luminaire housing  12  is preferably comprised of an upper top wall  40  and four sidewalls  42 , 44 , 46 , 48  depending from an outer peripheral edge of the top wall  40 , but may be of any configuration and such is felt to fall within the teachings herein. 
     The top wall  40  preferably has vents  15  for allowing air handling between an air plenum and the air handling luminaire  10  of the present invention. For example, some ventilation systems use the space between building floors as an air plenum. A fan is often provided to cause a negative pressure in the space between the floors. The negative pressure in cooperation with the vents  15  pull air from a room or area into the space between floors. The vents  15  also allow heat from the lamp tubes  18  to escape and thus prevent overheating of the luminaire  10 . 
     Within the housing  12  is at least one, preferably two, concave reflectors  22 . The reflectors  22  are preferably made of metal and have a reflective coating thereon. The preferably two concave reflectors  22  may extend from the lower ends of sidewalls  42 , 44  and connect with a ballast channel  20  near the center of the luminaire housing  12 . The ballast channel  20  is centrally aligned in the luminaire housing  12  and extends from sidewall  46  to sidewall  48  along top wall  40 , in this embodiment. An upper portion  20   a  of the ballast channel  20  contains conductors, wire nuts, and the like typically present in air-handling luminaires. This upper portion  20   a  is closed or sealed to prevent fire from reaching therein as well as protecting the conductors from dirt, dust, and the like. 
     A lower portion  20   b  of the ballast channel  20  contains a plurality of vents  17  in vertical walls which make up the ballast channel  20 . These vents  17  are in fluid communication with vents  15  in the top wall  40  of luminaire housing  12 . Thus, vents  17  are also in fluid communication with an air handling plenum (not shown) for moving air into or out of a room, office, or indoor area. An air gap  23  is in fluid communication with vents  17  and  15  and is formed by the ballast channel  20 , housing  12 , and reflectors  22 . The air gap  23  allows airflow from a room or area served by the air handling luminaire  10  to an air plenum above the ceiling level of the room or area. 
     Connected to the outer surface of the luminaire housing  12  is a heat distortion device or support clip  30 . The support clip may be formed of laminated dissimilar metals, dissimilar ceramics, ceramic metal combinations, or the like. Various other materials may be utilized which include combinations of material which deform under high temperature but which do not melt. Thus, the teachings herein are felt to cover various materials which distort before melting in order to release support for the light shield before the temperature is so high as to cause actual melting thereof. 
     The support clip  30  is preferably substantially L-shaped having a first long leg  30   a  and a second short leg  30   b . The support clip or heat distortion device  30  may be, for example, made of a bi-metal laminate having an industry designation of P675R. Using dissimilar metals causes the support clip  30  to non-permanently distort or extend away from the luminaire housing  12 , as shown in FIG. 3 in broken lines, when introduced to a predefined temperature. 
     In a preferred embodiment, the first long leg  30   a  has an upper portion with an aperture  32  located therein. Through aperture  32 , a screw, a bolt, or a rivet  33  attaches the upper portion of the support clip  30  to the luminaire housing  12 . 
     When the support clip  30  is attached to and integral with the luminaire body  12 , the short leg  30   b  must be oriented toward the luminaire housing  12 . During installation, the short leg  30   b  of the support clip  30  must extend through the luminaire housing  12 . 
     Also located adjacent to and preferably within the sidewalls of the luminaire body is a lamp shield  14 . The lamp shield  14  is preferably concave in shape and made of a microperforated metal. The microperforations provide an awareness of the light source by producing a glow from and around the lamp shield instead of a dark and shadowy area. The lamp shield  14  is also preferably flexible to allow for easy removal and/or opening of the luminaire for changing of the bulbs. 
     The lamp shield  14  also preferably has a plastic inlay or film  16  on an inner surface of the shield  14 . The film  16  also helps to provide a glow along with other desirable lighting characteristics. The film  16  is preferably a soft white colored film producing a soft white lighting effect desirable for office illumination, but may be any desired color. The plastic film  16  conceals a direct image of a lamp tube  18  through the microperforations and provides balance between reflected light and direct light. The lamp  18  may be preferably a fluorescent tube such as, for example, a high lumen compact fluorescent tube. The lamp shield  14  is supported from above in a hanging configuration to depend from the short leg  30   b  of the support clip  30  which is extended interiorly through the luminaire body  12 . Preferably, the luminaire housing  12  has a pair of holes  47 , 49  in sidewalls  46 , 48  and the lamp shield  14  has at least one hole or flange  19 . The pair of holes  47 , 49  are aligned with holes or flanges  19  on the lamp shield  14  such that when short leg  30   b  of the support clip  30  extends through the sidewalls  46 , 48  the short leg  30   b  extends through or under the hole or flange  19  to provide support. Preferably, four support clips  30  are used, one at each corner of the lamp shield  14 , to support the lamp shield  14 . Adjacent the sidewalls  42 , 44 , 46 , 48  are T-grids  24  which support ceiling tiles and connect the ceiling tiles with the air handling luminaires  10  to provide an aesthetically pleasing appearance for a suspended ceiling. The T-grids  24  can be either standard T-grids, exposed slot T-grids, or the like. 
     In use the air handling luminaire is connected to a return air duct or positioned adjacent a space used as a plenum, such as between floors in a commercial building. The vents  15  and  17  are in fluid communication with an air handling plenum and thus may be used to remove air from a room. The support clips  30  are connected to the upper portions of sidewalls  46 , 48  using rivets or screws  33 . The short leg  30   b  of the support clips  30  should extend through apertures or holes  47 , 49  in sidewalls  46 , 48  of the luminaire housing  12  and the lamp shield  14  allowing support of the lamp shield. 
     To clean the luminaire  10 , one may flex the lamp shield  14  so that the flanges  19  are free of the short legs  30   b  along a long side of lamp shield  14 . Once free, the lamp shield  14  will hinge along opposed flanges  19  opposite side and hang in an open position, as shown by dotted line in FIG.  1 . From this position, the lamps  18  can be changed or the film  16  can be cleaned. To close the lamp shield  14 , simply rotate the lamp shield  14  closed and flex the lamp shield  14  until the flanges  19  clear over the short legs  30   b.    
     When the air handling luminaire  10  is exposed to high heat conditions, such as during a fire, the support clip  30  extends away from the sidewall  46 , 48  as shown in FIG.  3 . In doing so, support for lamp shield  14  is removed causing it to fall from the air handling luminaire  10 . Thus, the plastic inlay or film  16  cannot burn near the air plenum which inhibits spread of fire or smoke through a building. 
     The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom for modifications will become obvious to those skilled in the art upon reading this disclosure and may be made without departing from the spirit of the invention and scope of the appended claims.