Patent Publication Number: US-7901105-B2

Title: Lighting device and lens assembly

Description:
FIELD OF THE INVENTION 
     The present invention is directed to a troffer or lighting fixture having a lens cover assembly. The invention is particularly directed to a lighting fixture having a lens cover assembly with a lens and a reflector where the cover assembly is hinged to a main housing and the lens and reflector are coupled to opposed end walls. 
     BACKGROUND OF THE INVENTION 
     Numerous lighting fixtures for directly illuminating areas are known. A common lighting assembly used in commercial buildings includes a troffer with one or more fluorescent lamps mounted therein. The lighting fixture can have a removable grid attached to the housing to allow access to the lamps for replacement. The reflectors are generally mounted to the housing. Other forms of lighting assemblies include a hinged or removable cover having a reflector and a lens that cooperate with the lamp in the closed position. The lamps are positioned inside the lens and the reflector is spaced from the lens to direct the light to the selected area to be illuminated. 
     Lighting assemblies are constructed to provide various needs and address certain lighting problems. The lighting assembly attempts to balance the required illumination of horizontal surfaces and vertical surfaces to provide the desired light quality. Difficulties often occur in smaller areas to avoid shadows or bright spots. 
     The lighting assemblies can use various lamp shapes and designs. The fluorescent lamp has been used frequently for many years. The fluorescent lamps are available in various sizes depending on the size of the lighting assembly. A disadvantage of many conventional fluorescent lamps is the brightness and glare which can be objectionable when viewed directly. These lighting assemblies often include opaque shielding or lenses to cover the lamp. The lens often includes prisms to diffuse the light and soften the glare. Various efforts have been made to provide lenses and shielding to reduce the brightness and glare of the fluorescent lamp. Examples of this form of lighting assembly are found in U.S. Pat. No. 5,988,829 to Holder, U.S. Pat. No. 7,229,192 to Mayfield et al., U.S. Pat. No. 6,280,052 to White and U.S. Pat. No. 7,261,435 to Gould et al. 
     Another example of a light fixture is disclosed in U.S. Pat. No. 7,296,910 to Mayfield et al. This light fixture includes a housing having a mounting assembly for the light and reflectors mounted on each side of the light and attached to the housing. A lens is hooked to the reflector around the light. The lens is removable from the reflector and the housing to access the light.&#39; 
     U.S. Published Patent Application No. 2007/0211457 to Mayfield discloses a replacement light fixture and lens assembly. The lens assembly can have a lens that hooks onto the ends of a reflector. The lens can also be mounted as a single piece with portions being painted to form reflector areas around a transparent lens portion. 
     While the prior lighting assemblies have generally been successful for the intended purpose, there is a continuing need in the industry for improved lighting assemblies. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a troffer or lighting fixture assembly for mounting to a ceiling. More particularly, the invention is directed to a lighting fixture having a cover or door in the form of a lens assembly hinged to the main housing of the lighting fixture where the cover includes at least one lens, at least one reflector, and a pair of opposed end walls. 
     The lighting assembly of the invention includes a main housing which supports the lamp and electrical components and a hinged cover and lens assembly connected to the housing. The cover formed by the lens assembly includes at least one reflector and a lens. The lens is positioned to overlie the lamp when the cover is in the closed position. The reflector is positioned adjacent the lens to reflect light passing through the lens in the desired direction. 
     One aspect of the invention is to provide a lighting assembly that is easy to construct and assemble. The lighting assembly preferably has a removable cover that includes a reflector and lens assembly and two opposed end walls, without the need for additional structural members or a large number of fasteners. Preferably, the lighting assembly is constructed to prevent light leakage from the housing to minimize shadows and glare. 
     Another aspect of the invention is to provide a cover for the lighting assembly where the reflector, lens and end walls form the lens assembly and the cover which can allow access to the lamp when the cover is in the open position. The cover is hinged to the housing and is latched in the closed position. 
     A further aspect of the invention is to provide a lighting assembly having a cover where the reflector and lens are secured directly to the cover for allowing easy access to the lamp and electrical components. 
     Another aspect of the invention is to provide a lens assembly for a lighting assembly having a lens with a longitudinal length greater than the longitudinal length of the body such that the ends of the lens extend beyond the ends of the cover a predetermined distance. In one embodiment of the invention, the end walls of the lens assembly include tabs to prevent longitudinal movement of the lens with respect to the lens assembly. 
     The various aspects of the invention are obtained by a lens assembly for directing light emitted from a light source toward a designated area, the lens assembly comprising a body having a first end wall and an opposite second end wall. The first and second end walls have a bottom edge and a top edge with a recessed area. A lens has a longitudinal dimension and an outer configuration and outer dimension complementing said recessed area in said end walls. The lens is received in said recessed areas of the end walls. 
     The various aspects of the invention are also obtained by providing a light fixture for directing light toward a designated area, where the light fixture includes a body supporting a light source for emitting light and a lens assembly hinged to the body. The lens assembly comprises a body having a first end wall and an opposite second end wall. Each of the end walls have a bottom edge and a top edge, where each top edge has a recessed area. A lens has a longitudinal dimension and an outer configuration and dimension complementing the recessed area in the end walls. The lens is received in recessed areas and supported by the end walls. 
     The aspects of the invention are further obtained by providing a lighting assembly for directing light toward a designated area, where the assembly comprises a main housing supporting a lamp and lens assembly. The housing has opposite side walls and opposite end walls, with the lamp extending between the opposite end walls. The lens assembly is hinged to the housing. The lens assembly comprises a first end wall having a bottom edge and a top edge with a recessed area, a second end wall having a bottom edge and a top edge with a recessed area, and a lens having a longitudinal dimension with an open top end and being received in the recessed areas and supported by the end walls. A first reflector extends between and is coupled to the end walls. The first reflector has a top end coupled to a first edge of the top end of the lens. A second reflector extends between and is coupled to the end walls. The second reflector has a top end coupled to a second edge of the top end of the lens. The second reflector is positioned on a side of the lens opposite the first reflector. 
     Another aspect of the invention is to provide a lighting fixture and lens assembly for directing emitted light from a light source. The lens assembly comprises a first end wall and second end wall opposite the first end wall. A first reflector having a longitudinal dimension with a first end is coupled to the first end wall by a fastener and a second end is coupled to the second end wall by a fastener. A second reflector having a longitudinal dimension with a first end is coupled to the first end wall by a fastener and a second end is coupled to the second end wall by a fastener. The second reflector is spaced from the first reflector to form a longitudinal opening between the first and second reflectors. A lens having a longitudinal dimension greater than the longitudinal dimension of the first and second reflectors is received in the opening. 
     The aspects of the invention are also attained by providing a lens assembly kit. The kit includes a housing having a first end wall and an opposite end wall, a first reflector extending between the first and second end walls and a second reflector extending between the first and second end walls and being spaced apart to define a longitudinal opening. The kit includes a first lens having a dimension corresponding to the opening and having a first shape, and a second lens having a dimension corresponding to the opening and having a second shape that is different from the first shape. 
     These and other aspects of the invention will become apparent from the following detailed description of the invention which, in conjunction with the annexed drawings, disclose various embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following is a brief description of the drawings in which: 
         FIG. 1  is a bottom perspective view of the lighting assembly in a first embodiment of the invention; 
         FIG. 2  is a bottom perspective view of the lighting assembly of  FIG. 1  showing the lens assembly and cover in an open position; 
         FIG. 3  is a cross-sectional view of the lighting assembly taken along line  3 - 3  of  FIG. 1 ; 
         FIG. 4  is a top perspective view of the lens assembly removed from the lighting assembly; 
         FIG. 5  is an exploded perspective view of the lens assembly; 
         FIG. 6  is a partial enlarged cross-sectional view of the clip coupling the lens to the reflector; 
         FIG. 7  is a partial perspective view of the clip coupling the lens to the reflector; 
         FIG. 8  is a perspective end view showing the lens coupled to the lens assembly; 
         FIG. 9  is an end view of the lens of the embodiment of  FIG. 1 ; 
         FIG. 10  is a side view of the clip connecting the lens to the reflector; 
         FIG. 11  is a top plan view of the clip of  FIG. 7 ; 
         FIG. 12  is a perspective view of the lighting assembly in a second embodiment of the invention; 
         FIG. 13  is a cross-sectional view taken along line  10 - 10  of  FIG. 9 ; 
         FIG. 14  is a perspective view of the lighting assembly of  FIG. 9  showing the cover in the opened position; 
         FIG. 15  is a perspective view of the lens assembly in a third embodiment of the invention; 
         FIG. 16  is a perspective view of the lens assembly in a fourth embodiment of the invention; and 
         FIG. 17  is a perspective view of the lens kit assembly showing the lens body and three lenses for assembling with the lens body. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed to a troffer or lighting assembly having a hinged cover and lens assembly. In particular, the invention is directed to a lighting assembly having a cover and lens assembly hinged to a main housing where a lens assembly includes a reflector and a lens and a pair of opposed end walls. The lens assembly of the invention has a minimum number of parts and fasteners. 
     Referring to  FIGS. 1-11 , a first embodiment of the invention is shown of the lighting assembly  10 . Lighting assembly  10  includes a main housing  12  and a lens assembly  14  which defines a cover or door for enclosing the main housing  12 . 
     Referring to  FIG. 2 , main housing  12  includes side panels  16  and top wall  18  and side walls  20 . As shown in  FIG. 2 , side walls  20  have a slightly curved shape and are inclined with respect to top wall  18  to define an internal cavity  22  of main housing  12 . Main housing  12  and its components are typically made of sheet metal that is cut and folded to the desired shape. 
     Side end panels  16  include mounting brackets  24  for mounting lighting assembly  10  to a ceiling or other support structure. Mounting brackets  24  are typically constructed to mount to a T-bar of a suspended ceiling as commonly used in building construction. At least one knock-out or pry-out plug  26  is provided in side end panel  16  for supplying electrical wiring to the lighting assembly. 
     In the embodiment illustrated, top wall  18  and side walls  20  are formed from a single sheet of metal that is bent and folded to enclose the top side of main housing  12 . Top wall  18  and side walls  20  are provided with tabs  28  on the opposite ends of top walls  18  and side wall  20 . Tabs  28  are inserted through slots  30  formed in side panels  16  and are bent over to secure the assembly together. 
     As shown in  FIG. 2 , top wall  18  has a bottom side facing internal cavity  22  and supporting a ballast cover  32  enclosing a ballast and wiring and lamp bases  34 . Lamp bases or sockets  34  are provided on each end of top wall  18  to support a lamp  36 . In the embodiment shown in  FIGS. 1-8 , a single lamp  36  is shown on opposite sides of ballast cover  32  and main housing  12 . In other embodiments, more than one lamp can be provided depending on the desired lighting properties. Lamp  36  is shown as a single fluorescent tube although other lamp arrangements can be used. In the embodiment illustrated, a socket pan  38  is coupled to top wall  18  to define a channel for supplying electrical wiring from the ballast  32  to each lamp base  34 . A bottom rail  40  extends between side panels  16  at a lower end of side walls  20  as shown in  FIGS. 1 and 3 . Bottom rails  40  are provided on each end of main housing  12  and secured to side end panels  16  and coupled to side walls  20 . 
     Lens assembly  14  is coupled to main housing  12  in a manner to pivot between an opened and closed position shown in  FIG. 2  to allow access to lamps  36  and the electrical components within main housing  12 . Lens assembly  14  defines a cover or door assembly that is removably coupled to housing  12 . Bottom rails  40  of main housing  12  include an aperture for receiving a hinge member  50  on lens assembly  14  to allow lens assembly  14  to pivot to an open position. Hinge member  50  in the embodiment illustrated is a hook-shaped member formed at opposite ends on one side of lens assembly  14 . Hinge member  50  is inserted through the aperture in bottom rail  40  and slides within the aperture between an open and closed position. The opposite end of lens assembly includes a pair of latch members  52  which latch into a complimenting aperture in the corresponding bottom rail  40 . Latch members  52  are pivotally connected to cover  14  by pivot pin  54 . Latch  52  in the embodiment illustrated has a hook portion  56  and an operating tab  58 . A spring is preferably provided to pivot latch  52  in a locking direction. Alternatively, a sliding latch can be provided to engage bottom rail  40  of main housing  12 . Preferably, latch members  52  are provided at opposite corners of lens assembly  14 . 
     Lens assembly  14  has a shape and dimension to fit within cavity  22  of main housing  12  and to form a cover or door to close the open bottom end of main housing  12 . Lens assembly  14  includes opposite end walls  60 , curved side reflectors  62  and a center reflector  64  which form a body  63  of lens assembly  14 . End walls  60  are substantially mirror images of each other and have a bottom edge  66  formed with an upturned lip  68 . End walls  60  are formed from a sheet material such as sheet metal that is cut and formed into a desired shape. Lip  68  is bent at right angles to form bottom edge  66 . In the embodiment shown, lip  68  extends upwardly in a direction substantially parallel to the plane of end wall  60 . 
     End walls  60  have a top edge  70  and side edges  72 . Side edges  72  in the embodiment shown are inclined with respect to the longitudinal dimension of lens assembly  14  so as to fit within the internal cavity  12  of main housing  22  as shown in  FIG. 3 . End wall  60  has a plurality of slots  74  which receive tabs  76  of the corresponding reflectors  62  and  64 . The tabs  76  are inserted through the respected slots  74  and bent against the face of end wall  60  to attach the reflectors to the end walls. The tabs  76  can be spot welded as needed to secure the parts together. This arrangement enables the construction of the lens assembly with a minimum number of parts and fasteners while providing the necessary rigidity of the lens assembly. As shown in the embodiment of  FIG. 5 , two spaced-apart substantially V-shaped recess portions  78  are formed along the top edge  70  to receive a lens  80 , which are also known as diffusers. The recessed portions  78  are shown as having a substantially V-shape, although the recessed portions can have other shapes or profiles. As discussed herein, the shape or profile of the recessed portions correspond to the shape or profile of the lens. Side reflectors  62  are coupled to end walls  60  and extend between bottom edge  66  and the upper outer edge  82  of the V-shaped recesses  78 . Side reflectors  62  have a substantially curved shape with a concave downwardly facing surface. Center reflector  64  as shown in  FIG. 3  has a substantially V-shape forming two curved reflector panels  84 . The two reflector panels  84  converge to an apex adjacent bottom edge  64  of end walls. Each reflector panel  84  of center reflector  64  extends from bottom edge  66  to an upper inner edge  86  of each recess  78 . In the embodiment illustrated, side reflectors  62  and reflector panels  84  have a slightly arcuate shape with a concave surface facing downwardly for reflecting light in a downward direction with respect to lighting assembly  10 . In other embodiments, the reflectors can be a flat surface or multifaceted surface as desired. End walls  60  and reflectors  62  and  64  are preferably made of sheet metal. The assembled end walls and reflectors form a lens housing which also operate as a cover for the main housing of the body. 
     Referring to  FIG. 8 , recess  78  in end walls  60  form a substantially V-shape with a pair of inclined edges  88  that converge downwardly toward bottom edge  66  and open upwardly to top edge  70 . Each inclined edge  88  is provided with a stop member  90  to position lens  80  within the respective V-shaped recess  78  to limit longitudinal movement of lens  80 . Stop member  90  in the embodiment illustrated is an L-shaped member having a first leg  92  extending substantially perpendicular to the plane of end wall  60  adjacent the inclined edge  88 . A second leg  94  extends in a generally upward direction perpendicular to the plane of first leg and parallel to the plane of end wall  60 . As shown in  FIG. 8 , second leg  94  extends inwardly with respect to V-shaped recess  78 . 
     Each lens  80  has a shape complementing the shape and dimensions of recess  78 . In the embodiment illustrated, lens  80  has a longitudinal length with a longitudinal end  96 . Lens  80  is formed with two side panels  98  that converge to an apex  100  at a bottom end as shown in  FIG. 9 . An inwardly extending flange  102  extends inwardly from a top edge  104  of each of side panels  98 . 
     As shown in  FIGS. 3-5 , each lens  80  is received within the respective recess  78  and has a longitudinal length greater than the spacing between the end walls  60 . As shown in  FIG. 5 , the longitudinal ends  96  of lens  80  extend outwardly from the outer surface of end walls  60 . Ends  96  of lens  80  are received within the L-shaped stop member  90  which resists longitudinal movement of lens  80  with respect to cover  14 . Preferably, side panels  98  of lens  80  seat against the inclined edges  88  to minimize or eliminate light leakage. 
     As shown in  FIGS. 2 and 3 , the upper end of side reflectors  62  and center reflector  64  overly flanges  102  of the respective lens  80 . Side reflectors  62  have a bottom edge  106  with an upturned lip  108 . A top edge  110  of side reflectors  62  are preferably aligned with the inner edge of flange  102  of the respective lens. Upper edge  110  of side reflector includes an upturned lip  112  that extends upwardly substantially perpendicular to the main portion of side reflector  62 . 
     Each lip  112  has an aperture  114  for receiving a spring clip  116  for coupling lens  80  to reflectors  62 . As shown in  FIGS. 10 and 11 , spring clip  114  has a first leg  116  and a second leg  118  that are spring biased toward each other. First leg  116  is provided with an operating tab  120  extending substantially perpendicular to first leg  116  for manipulating spring clip into and out of engagement with the reflector and lens. Locking teeth  122  are provided on the first leg  116  and second leg  118  for gripping the reflector and lens. First leg  116  is passed through aperture  114  and lip  112  so that the spring clip grip the outer edge of the respective reflector and the inner edge of the respective flange  102  of lens  80 . As shown in  FIGS. 3 and 5  center reflector  64  has a top edge  124  and upturned lip  125  with an aperture  126  for receiving a spring clip  115  and coupling the respective lens to the center reflector  64 . 
     Lens  80  is typically made of a plastic material and is sufficiently rigid to prevent bending and twisting. Lens  80  can be clear, frosted or include prisms on an inner or outer surface as desired. Lighting assembly  10  is typically mounted to a ceiling or other support structure in a standard manner. Main housing  12  is typically mounted to the ceiling or T-bar support of a suspended ceiling and suitable wiring (not shown) is connected to the ballast and other electrical components in main housing  12 . Lens assembly  14  is connected to main housing by hinge hooks  50  and pivoted to the closed position shown in  FIG. 1 . As shown in  FIG. 2 , each lens  80  is aligned with the respective lamp  36  so that light passes through the respective lens and is directed in a downward direction by the reflectors. Preferably, main housing  12  and cover  14  are constructed to minimize light leakage around the top and side edges so that substantially all of the light is reflected in a downward direction to the selected target area to be illuminated, with cover  14  being formed of a minimum number of parts, structural members and fasteners. 
     Referring to  FIGS. 12-14 , a second embodiment in the invention is illustrated. This embodiment is similar to the embodiment of  FIGS. 1-11 . Lighting assembly  130  as shown in  FIGS. 12 and 13  includes a main housing  131 , end walls  132 , side walls  134  and a top wall  136 . A ballast cover  138  is attached to the inner surface of top wall  136  to enclose a ballast and electrical wiring. An electrical cover  140  extends between ballast cover  138  and side wall  134  to enclose electrical components. A socket pan  142  extends along each end wall  132  for supporting lamp base  144  and enclosing wiring supplied to each lamp base  144 . In the embodiment illustrated, two lamp bases  144  are mounted adjacent each other for supporting two parallel lamps  146 . 
     A lens assembly  148  is constructed in similar manner as the embodiment of  FIGS. 1-11 . Lens assembly  148  includes side reflectors  150  that are coupled to end walls  152  by tabs  154  that are inserted through a respective hole in end walls  152 . 
     End walls  152  have a bottom edge  156  with an upturned lip  158 . A top edge  160  of end walls  152  has a single recess  162  to receive a lens  164 . The recess  162  in this embodiment has a substantially V-shape corresponding to the shape of the lens  164 . End walls  152  include L-shaped stop members  166  adjacent recess  162  to limit longitudinal movement of lens  164  as in the previous embodiment. 
     Lens  64  has a substantially V-shape as in the previous embodiment with inwardly extending flanges  168 . Side reflectors  150  have an upper edge  170  with a flange  172  extending in an upward direction. Flange  172  includes an aperture  174  for receiving a spring clip  177 . Spring clip  177  is constructed substantially the same as in the previous embodiment. 
     Lighting assembly  130  is used in a similar manner by mounting the main housing in the ceiling. Cover  148  is connected to main housing  131  by hinge members to pivot from the closed position shown in  FIGS. 9 and 10  to the opened position shown in  FIG. 14 . A latch member  178  is included to latch cover  148  in a closed position. 
     In the embodiments illustrated, the lens is shown as having a substantially V-shape with flat side panels to form a generally triangular-shaped cross-section as shown in  FIG. 9 . In other embodiments, the lens can have various shapes and dimensions depending on the desired appearance of the lighting assembly. In an alternative embodiment shown in  FIG. 15 , a lens assembly  180  is provided with a lens  182  having a generally curved bell-shaped or concave-convex profile commonly referred to as a cyma-shape. Lens assembly  180  is constructed in a manner similar to the embodiment of  FIGS. 1-11 . It will be understood that other shapes and profiles of the lens can be used. A further embodiment is shown in  FIG. 16 . In this embodiment, lens assembly  184  has a lens  186  with curved side panels  188  which form a modified substantially V-shaped cross-section with convex outer profiles or surfaces. Lens assembly  184  is constructed in substantially the same manner as the previous embodiments. 
     In another embodiment of the invention shown in  FIG. 17 , a lens assembly kit  200  is provided which includes a lens housing  202  and at least two lenses, and preferably three lenses  204 ,  206  and  208  having different shapes. The lens of the desired shape is selected by the user and assembled to the lens housing  202  as in the previous embodiments. 
     While various embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made without parting from the scope of the invention as defined in the appended claims.