Abstract:
A halogen light fixture for mounting under a cabinet and over a counter surface, as in a kitchen, has a housing between opposite end caps adaptable to fixtures of varying lengths. A partition between the end caps cooperates with a housing top and rear wall to provide a closed wiring compartment including a power switch accessible on a bottom of the partition. A translucent diffuser panel is supported in open slots formed in the end caps and can be pulled from the slots for access to the lamps sockets. The fixture is held together by screws passing through the housing and the end caps.

Description:
[0001]    This is a Continuation of application Ser. No. 11/530,898 which is a division of application Ser. No. 10/406,968 filed Apr. 3, 2003, now U.S. Pat. No. 7,114,833, which is a continuation of application Ser. No. 09/340,071 filed Jun. 25, 1999, now U.S. Pat. No. 6,565,234 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention pertains generally to the field of lighting fixtures and more particularly is directed to a fixture for mounting to the underside of a cabinet over a counter surface, such as in a kitchen, and featuring halogen lamps as the light source. 
         [0004]    2. State of the Prior Art 
         [0005]    Counter light fixtures constitute a substantial segment of the indoor lighting market and generally include lamp fixtures which can be mounted to the underside of wall-mounted cabinets, such as kitchen cabinets, for the purpose of illuminating a counter area under the cabinets. It is desirable that such counter lights have a slim profile for unobtrusive mounting under the cabinets. Many such fixtures are commercially available and typically rely on fluorescent lamp tubes as the light source. Counter lights are generally between one and two inches in height and of varying length depending on the length of the counter surface to be illuminated. The light fixture is commonly fastened by screws passing through mounting holes in the housing of the light fixture and driven into the wooden cabinet. Electrical power may be supplied to the fixture either by a power cord which is plugged into an A.C. wall outlet, or by an electrical conduit connected through a “knock-out” opening in the fixture housing. 
         [0006]    A common problem in counter light fixtures is excessive heat buildup which is transferred to the cabinet above the fixture and eventually heats the cabinet interior. Temperature sensitive food stuffs or other materials stored in such a cabinet can be degraded or spoiled by the heat. The proximity of a hot lamp fixture to a counter surface is also undesirable for reasons of safety and comfort of those working there. 
         [0007]    This problem is aggravated by halogen lamp bulbs which run hot compared to fluorescent tubes. The relatively small interior space of the lamp housing and its close proximity to the cabinet overhead prevents easy dissipation of rising hot air and conspires against easy ventilation of the lamp housing. 
         [0008]    Existing counter lights also are unduly difficult and inconvenient to install because of the difficult access to the electrical wiring in the fixture. Often a wiring compartment is secured by multiple fasteners, such as sheet metal screws, which must be removed and replaced during installation. Replacement of such fasteners is difficult because it has to be made after the fixture is fastened to the underside of the cabinet, forcing the electrician to work in an awkward position. 
         [0009]    What is needed is a halogen lamp counter light fixture with improved ventilation and heat dissipation characteristics and which is easier to install underneath hanging cabinets than currently available light fixtures. 
       SUMMARY OF THE INVENTION 
       [0010]    This invention addresses the aforementioned needs by providing an improved counter light fixture having a housing which includes a housing cover extending between opposite end caps, and a removable interior partition also extending between the opposite end caps. The partition can be resiliently flexed by modest manual force into and out of retentive snap engagement with the housing cover thereby to define a substantially closed wiring compartment. A lamp socket and an electrical switch are on an outer side of the partition and are interconnected by electrical wiring on the inner side of the partition. The partition can be readily removed from and replaced on the cover without use of fasteners for more convenient access to the wiring during installation of said light fixture. 
         [0011]    In a presently preferred fixture housing the cover also has a front and a rear extending downwardly from a generally planar center. The partition has a rear edge contained against the rear wall, and a front edge releaseably engageable to the planar center for retaining the partition to the cover under inherent spring force. The front edge of the partition may have a tab retained in a slot defined in the cover. The front edge is readily disengageable from the housing top by momentarily pressing against the spring force of the compressed partition to release the tab from the slot. The opposite end caps may be molded plastic fittings, and the front, center and rear of the housing top is preferably a single sheet of metal contained and supported between the plastic caps. 
         [0012]    The light fixture has a reflector fixed to the underside of the housing top, and the partition is sized, shaped and configured to position a lamp inserted in the socket in predetermined relationship with the reflector. A heat shield plate is interposed between the reflector and the underside of the housing top. The reflector and the shield plate may be supported on a small number of small diameter metal rivets in spaced relationship from the underside to limit conduction of heat from the heat shield plate to the housing. For example, both the reflector and the plate may be mounted on one pair of such rivets. One or more vent openings are defined through the housing in overlying relationship with the heat shield plate such that hot air rising from a lamp in the socket is forced to flow around the plate and then into a cross flow space defined between the plate and the underside before exhausting through the vent openings. 
         [0013]    A translucent light diffuser panel is supported to the housing under the reflector. The panel has a panel front edge and a panel rear edge. The panel front edge is spaced from the front of the housing top, and the panel rear edge is spaced from the interior partition thereby defining a front air gap and a rear air gap respectively to admit air flow upwardly into the housing for exhaust through the vent openings in the housing top thereby to cool the housing during operation of the light fixture. The diffuser panel is partially supported in front slots defined in the molded plastic end caps and secured against separation from the housing by a single screw passing through a screw hole in the panel and threaded into the housing top. The single screw may be threaded into a bracket permanently attached to the sheet metal housing top. 
         [0014]    Mounting screw holes are provided through the cover and the end caps. The end caps have integral external spacer portions raised above the top surface of the cover, such that the sheet metal cover is spaced from an overlying mounting surface such as a wall cabinet when fastened thereto by screws passing through the screw holes. This spacing facilitates the exhaust of hot air through the vents. The molded plastic end caps preferably have knockouts removable for opening one or more holes and admitting electrical wiring into the wiring compartment to supply power to the light fixture. 
         [0015]    As presently preferred, the housing of the counter light fixture has a first metal sheet bent in a transverse dimension to a predetermined cross section and a pair of molded plastic end caps grooved for receiving opposite side edges of the first metal sheet thereby to supports and retain the predetermined cross section of the metal sheet. A second metal sheet is bent along a transverse dimension parallel to the transverse dimension of the first metal sheet. The second metal sheet is installed as a partition in the housing to define therewith a wiring compartment between the end caps. The partition also serves as a mounting chassis for a lamp socket and an electrical switch mounted on the second metal sheet. Electrical wiring on an interior side of the second metal sheet interconnects the socket and the switch with power supply conduit or cord. The second metal sheet flexes under modest manual force into and out of retentive snap engagement with the first metal sheet such that the metal sheets can be readily separated without tools for access to the wiring. Neither the first nor the second metal sheets are bent along their longitudinal cross sections so that the cross section of the two metal sheets remains essentially the same along the length of the lamp fixture between the plastic end caps. As a result, the counter lamp fixture can be easily made in different lengths using the same end caps and with one or more lamp socket/reflector/heat shield assemblies spaced along the length of the fixture. For example, one lamp, two lamp and three lamp fixtures are contemplated of successively greater length but similar cross section. 
         [0016]    These and other features, advantages and improvements of the present invention will be better understood from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a perspective view of a single-lamp counter light fixture according to this invention; 
           [0018]      FIG. 2  is a bottom plan view of the light fixture of  FIG. 1  with the diffuser panel partly broken away to show the lamp reflector and heat shield plate arrangement; 
           [0019]      FIG. 3  shows the light fixture of  FIG. 1  with the interior partition removed from the housing cover to show the electrical wiring of the fixture; 
           [0020]      FIG. 4  is a cross sectional view of the light fixture taken along line  4 - 4  in  FIG. 2 ; 
           [0021]      FIG. 4A  is an enlarged view of detail area  4 A in  FIG. 4  showing the front air gap defined between the removable diffuser panel and the front of the housing cover for ventilation of the light fixture; 
           [0022]      FIG. 5  is a cross sectional view as in  FIG. 4  illustrating disengagement of the interior partition from the housing cover; 
           [0023]      FIG. 6  is a top plan view of the light fixture of  FIG. 1  depicting the vent openings for exhausting hot air and the plastic end caps of the fixture; 
           [0024]      FIG. 7  is a sectional view taken along line  7 - 7  in  FIG. 6 ; 
           [0025]      FIG. 8  is a bottom plan view of a two lamp version of the novel light fixture, shown without the diffuser panel to expose the two lamp reflectors and common heat shield plate; and 
           [0026]      FIG. 9  is a bottom plan view of a three lamp version of the novel light fixture, shown without the diffuser panel to expose the three lamp reflectors and common heat shield plate. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0027]    With reference to the accompanying drawings in which like elements are designated by like numerals,  FIG. 1  shows a counter light fixture  10  intended for mounting to the underside of a wall cabinet. Typically the fixture illuminates a counter surface under the cabinet, a typical arrangement in home kitchens. The light fixture  10  is intended to operate with halogen lamps, which run hotter than other conventional light sources. 
         [0028]    The lamp fixture has a fixture housing  12  which includes a cover  14  supported between two end caps  16 . The cover  14  may be a single sheet of metal bent in a transverse dimension to define a generally planar housing top  18  between a rear wall  20  and a downwardly extending front  22 . A removable interior partition  24  extends between the end caps  16  to define with the cover a wiring compartment  26  which runs the length of the housing  12 . The partition includes a front  25  with a top edge  27  and a tab  28  projecting from the top edge, a bottom  30  with a rear edge  32 , and side edges  34 . As best seen in  FIG. 5  the partition bottom  30  is transverse to rear wall  20  and partition front  25  is transverse to the partition bottom  30 . It is also seen that partition front  25  and partition bottom  30  are generally perpendicular to each other. 
         [0029]    The partition is assembled to the housing  12  by fitting the rear edge  32  against the rear wall  20  of the housing and pressing the front  25  towards the rear wall until it flexes sufficiently for tab  28  to align with and enter retaining slot  35 , a condition depicted in  FIG. 4 , such that the partition  24  is supported to the housing top  18 . The inherent restorative spring force of the slightly deformed partition keeps the tab in the retaining slot and secures the partition to the fixture housing, providing a snap-in mounting of the partition  24 . The partition is easily separated from the housing, without removing any screws or other fasteners and without use of any tools, simply by squeezing the front  25  slightly backwards along arrow P in  FIG. 5  to pull tab  28  out of the slot  35  and free the partition from engagement with the housing. The partition can then be separated and removed from the housing  12  for access to the interior of compartment  26  in the manner illustrated by  FIG. 3 . 
         [0030]    The partition provides a mounting chassis for the electrical components of the light fixture, namely power switch  36  mounted to the chassis bottom  30  and a lamp socket  38  mounted on the front  25  of the chassis. Switch  36  and socket  38  have terminal connectors interior to the compartment  26 , and are interconnected by electric wiring  40  as seen in  FIG. 3 . The chassis or partition  24  can be completely removed from the housing  12  for easy access to all electrical connections during installation of the fixture  10 . 
         [0031]    A light reflector  42  is mounted to an underside  44  of the cover  14  in overlying relationship to a lamp bulb  46  fitted into the lamp socket  38 . A heat shield plate  50  preferably of sheet metal is interposed between the cover  14  and reflector  42  for shielding the cover from heat radiated by the reflector. The reflector  42  and the plate  50  are supported on a pair of relatively small metal rivets  52  fastened to the cover  14 . The heat shield plate is supported on the rivets in spaced relationship to the underside  44  of the cover by spacer washers  55 , as shown in  FIGS. 4 and 5 , so that heat flow to the cover is limited to conduction by the rivets. However, the rivets have a small cross section and offer a relatively low conductivity heat flow path from the reflector and shield plate to the cover. A number of vent slots  54  are cut through the cover. The vent slots are disposed over the heat shield plate  50  which to some extent also serves as a light shield to block light leakage through the vent slots. The spacing between the plate  50  and the underside  44  of the cover defines a relatively narrow cross-flow space  56  which admits air flow from the interior of the lamp housing for exhaust through the vent slots  54 . 
         [0032]    During operation of the light fixture the reflector  42  becomes quite hot due to its close proximity to the halogen lamp bulb  46 . Dissipation of heat by conduction from the reflector is limited by the conductivity of the rivets  52 . Heat is however transferred to air around the reflector which then tends to rise in the housing  12 . The rising hot air encounters the undersurface of the shield plate  50 , which blocks direct upward air flow to the vents  54 , and is deflected laterally until it reaches the edges of the plate, at which point the hot air is again free to rise into the cross-flow space  56 . Since the vents lie over the plate  50 , the hot air is forced to flow laterally and generally horizontally into the cross-flow space and over the top surface of the plate in order to exhaust from the housing through the vents. This flow of air in close contact with both the undersurface and the top surface of the plate  50  tends to carry away heat from the plate and consequently reduces heat transfer from the plate to the housing cover  14 . This effect is enhanced by the narrow spacing between the plate and the cover which causes air flow to speed up in the restricted passage of cross-flow space  56 , thereby improving cooling of the shield plate  50 , before finally exhausting through vents  54 . 
         [0033]    The light fixture also has a rectangularly shaped prismatic light diffuser panel  60  of glass or other transparent or translucent heat resistant material. As best seen in  FIG. 4  the panel  60  is supported to the fixture housing partly by inserting the rear edge  62  into front slots  61  of the end caps  16 , and secured to the housing  12  by a single screw  64  which passes through hole  66  in the panel and threads into screw hole  68  in a bracket  70  permanently fixed, as by welding, to the cover  14 . The screw  64  has a knurled screw head  72  which can be turned without tools to facilitate initial assembly and installation of the fixture  10  and makes possible one-hand removal of the light diffuser panel  60  for cleaning. 
         [0034]    The front edge  74  of diffuser panel  60  is spaced from the lip  76  of the housing&#39;s downwardly sloping front  22 , to define a first air gap  78 , best seen in  FIGS. 4A and 7 . The rear edge  62  of panel  60  is similarly spaced from the front  25  of the partition  24  to define a second air gap  80 . Both air gaps  78  and  80  extend the length of the housing between end caps  16  along the bottom of the fixture, and admit cool ambient air into the housing to replace hot air exhausting through top vent openings  54 . As a result a steady flow of air passes through the fixture, cool air entering through the bottom and hot air exhausting through the top, during operation of the light fixture. 
         [0035]    Flow of air through the light fixture housing  12  is further facilitated by exterior spacers  82  rising above the housing top  18 , as best seen in  FIG. 7 . The spacers are preferably molded integrally with the plastic end caps  16 . The housing  10  is fastened to or hung from a mounting surface M by means of two mounting screws  86  inserted in key slot holes  88  through top sheet  14  and each of the end caps  16 , as seen in  FIGS. 6 and 7 . As best seen in  FIG. 7  each keyslot hole  88  includes aligned openings or holes  88   a  in the housing top  14  and  88   b  in the upper portion of end caps  16  for admitting fasteners  86  through the aligned openings for fastening the housing  12  to overlying mounting surface M. 
         [0036]    Spacers  82  hold the housing top away from the mounting surface M, e.g. the bottom of a wall hung cabinet, to provide a three-fold benefit. Firstly, the sheet metal housing top  18  is moved away from contact with the mounting surface M, thereby greatly reducing conductive heat transfer to the mounting surface. Secondly, an open exhaust space  84  is created between the fixture  10  and mounting surface M which provides an insulating layer of air and facilitates rapid diffusion of hot air exhausting through vent openings  54  into the environment. Thirdly, mounting surface M is insulated from the hot metal cover  14  by the plastic spacers  82 . 
         [0037]    Yet another feature of the light fixture  10  is that the cover has a constant profile along its length. That is, the cross-sectional shape of the cover is constant in the longitudinal dimension of the cover, from one end fitting  16  to the other, except for the various openings in the cover. Cover  14  is bent only across its width or transverse dimension, at a bend line  90  to define the rear wall  20  and a radius  92  to define the downward sloping front  22 , as indicated in  FIG. 5 . The bend line and radius also extend the length of the cover from one end fitting  16  to the other. The side edges of cover  14  fit in supporting grooves or structures in end caps  16  which support the cross sectional shape of the cover  14 . The end caps may be secured to the cover  14  by small screws  83  seen in  FIG. 6 . 
         [0038]    The cross sectional shape of partition chassis  24  also remains the same along its length. As a result, both cover  14  and partition  24  can be easily made in arbitrary lengths to accommodate more than one lamp socket and reflector assembly. The same end caps  16  may be used regardless of the length of the cover and partition, thereby simplifying manufacture of different sized light fixtures. Also, the same lamp socket/reflector/shield plate arrangement can be repeated at spaced intervals along the housing length to make multi-lamp fixtures. For example,  FIG. 8  shows a two lamp light fixture  10 ′, while  FIG. 9  depicts a three lamp light fixture  10 ″. Each of the fixtures  10 ′ and  10 ″ retain all the improvements, advantages and features of the single lamp fixture  10  described in connection with  FIGS. 1 through 7 , and common elements in the fixtures  10 ,  10 ′ and  10 ″ are designated by like numerals which are primed to indicate a change in dimensions but not function. Instead of separate heat shield plates for the multiple sockets, a single heat shield plate  50 ′ and  50 ″ common to the several lamps is provided in light fixtures  10 ′ and  10 ″, respectively, to reduce parts count since the plates are rectangular sheets and simple to make in any length. However, the ventilation features remain substantially the same in the longer fixtures, with exhaust vent openings (hidden behind the plates  50 ′,  50 ″ in  FIGS. 8 and 9 ) cut in the cover  14 ′,  14 ″ in overlying relationship to the heat shield plate. The extended fixtures  10 ′ and  10 ″ are shown without the diffuser panels to expose the interior. These fixtures are however provided with diffuser panels of length appropriate to the length of the fixture, and the diffuser panels define front and rear air gaps with the fixture housing as explained earlier in connection with FIGS  4 A and  7 . 
         [0039]    The end caps  16 , which require no modification for fixtures of any length, may be of injection molded plastic and each equipped with integrally molded “knockout”  86  which can be opened to pass electrical supply wiring into the interior compartment  26  of housing  12 . The knockouts in the end caps  16  can accommodate “wiremold” metal raceways, as well as Romex, flex conduit or rigid conduit. Additional knockouts may be provided in rear wall  20 . Electrical power to the light fixture  10  can be delivered either by a conventional A.C. power cord  94  passed through a grommeted hole in rear wall  20 , or for permanent installations suitable electrical conduit can be passed through any of the knockouts. 
         [0040]    In the light fixtures shown in the drawings A.C. power is connected directly to each lamp socket. This arrangement requires use of high voltage halogen lamp bulbs designed to operate at A.C. line voltage. The light fixtures may be adapted, however, to use of low voltage bulbs by providing a suitable transformer or power converter in the wiring compartment  26 . 
         [0041]    From the foregoing it will be appreciated that a light fixture of simplified construction and assembly, easier maintenance and installation, improved ventilation and cooler operation has been disclosed. 
         [0042]    While particular embodiments of the novel light fixture have been described and illustrated for purposes of clarity and example it should be understood that many changes, modifications and substitutions will be apparent to those having ordinary skill in the art without thereby departing from the scope of this invention, which is defined by the following claims.