Abstract:
A channel shaped track lighting fixture has a light reflector mounted in a pair of aligned internal grooves. Removable end caps permit access to the interior of the lighting fixtures so that the reflector may be slid out of the fixture along the aligned internal grooves.

Description:
This invention relates to a lighting fixture of the type for use in a track lighting system. In particular, the invention relates to a track lighting fixture of the type known as a wall washer. This type of lighting fixture is secured to the track of the system which in turn is secured typically onto a ceiling or overhead member adjacent a wall or other vertical surface to be illuminated. The wall washer is typically adapted to be pivoted in a vertical plane so as to direct light at the wall or vertical surface so as to illuminate a particular area or to achieve a particular lighting effect. These lighting fixtures are designed in many decorative shapes, and sizes but have been subject to certain shortcomings particularly in regard to ease of servicing. 
     As is the case with all lighting fixtures, it is of course, required to replace the light source or to service the light reflector such as by cleaning or replacing. Additionally, although required less frequently, it may be necessary to replace or service the lamp socket or electrical leads and connections. Present fixtures of the wall wash type are for the most part not designed for easy serviceability except possibly for the light source itself, therefore, it would be highly desirable to provide for a track light fixture having increased serviceability. 
     Also, the light sources used with these fixtures generate considerable heat and are normally enclosed in a relatively small housing which confines and concentrates the heat which can build during operation to undesireably high and even dangerous levels. Heretofore, the fixtures have been left open at the front with the light source exposed so as to provide for both servicing of the bulb as well as for access of cooling ambient air to the hot bulb and reflector. Leaving the bulb exposed can be dangerous and, therefore, it would be desirable to provide for a light transparent safety lens that also provides for access of cooling air to the housing interior. 
     Further shortcomings of prior art wall washers has been the inability to obtain sharp light cut-off at both the top and the bottom of the light pattern. Sharp light cut-off is desirable for framing an object or area or for evenly illuminating the subject surface beginning, for example, at the interface of a wall and ceiling. 
     Further, it is often desirable to attach accessory items to the fixture such as a color filter, baffle, or adjustable barn door type shutter for achieving a particular lighting effect. It can be appreciated that these accessory items are intended to be temporarily attached and interchangeable and therefore attachment and removal from the fixture should be simple, fast and positive. 
     SUMMARY OF THE INVENTION 
     The present invention provides for a wall wash track lighting fixture that is easily serviced, provides for cooler, safer operation than prior art fixtures and produces uniform sharp light cut off at the top and bottom of the light pattern. 
     According to an important aspect of the invention, the housing of the fixture is an elongated, extruded channel shaped member open at opposing ends and at the front. The housing is provided with at least two pairs of aligned grooves in the top and the bottom walls for slideably receiving from either end of the housing an asymmetrically-shaped reflector and a transparent planar safety lens. 
     According to another important aspect of the invention, the reflector is an elongated, asymmetrically shaped reflector extending between the ends of the housing providing for a uniform field of illumination having sharp light cut-off at the top and bottom of the light pattern. 
     According to another important aspect of the invention, a pair of removeable end caps are mounted at each end of the housing with a pair of springs which bias and hold the caps against the housing across the open ends and allow for alternative positioning of the end caps removed from the housing ends. 
     A still further important feature of the invention provides for stop means on each end cap and at least one retention tab adapted to retain the end cap to the housing when removed from the open end. 
     Another feature of the invention provides for the lens to have a length less than the spacing between the end caps whereby a pair of air openings into the interior of the housing is created between the end caps and each end of the lens. The openings allow cooler ambient air to enter and circulate through the housing to cool the interior thereof. 
     Yet another important feature of the invention provides for a novel mounting structure for mounting the housing to the track of the lighting system including an elongated strap-like bracket slideably received in a slot provided in the back wall of the housing and a Y-shaped hanger pivotally attached to the bracket. 
     A wall fixture constructed according to the principles of the present invention is easily assembled and disassembled for servicing and provides for uniform illumination and sharp light cut off at the top and bottom of the light pattern. Further, the fixture operates cooler and safer than present fixtures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The important features as well as other aspects of the invention will become apparent and better understood after reading the following detailed description taken in connection with the accompanying drawings wherein: 
     FIG. 1 is a perspective view of the lighting fixture of the present invention; 
     FIG. 1a is a perspective view similar to FIG. 1 wherein the housing has been rotated 90°; 
     FIG. 2 is a front view of the lighting fixture shown in FIG. 1; 
     FIG. 3 is a view taken along the line 3--3 of FIG. 1; 
     FIG. 4 is a sectional view along line 4--4 of FIG. 2; 
     FIG. 5 is a sectional view along line 5--5 of FIG. 2; 
     FIG. 6 is a sectional view along line 6--6 of FIG. 1; 
     FIG. 7 is a front view and partial section of the device of the present invention; 
     FIG. 8 is a perspective view of an alternate embodiment; 
     FIG. 9 is a view taken along the line 9--9 of FIG. 8; and 
     FIG. 10 is a component view of the device shown in FIG. 7. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Shown in FIGS. 1-4 is a wall wash track lighting fixture 10 including an elongated channel shaped extruded aluminum housing 12 having a top wall 14, a bottom wall 16 and a back wall 18 connected between the top and bottom walls. The housing is open at opposing ends 20, 22 and one end cap of a pair of end caps 24, 26 is mounted in each open end. As shown in the drawings, the housing is elongated forming a rectangular shaped frontal opening 28 behind which is mounted between the opposing ends an elongated asymmetrically shaped light reflector 30. The inner surfaces of the top wall 14 and the bottom wall 16 are provided with at least two pairs of aligned grooves 32, 34 and 36, 38 extending between the ends 20 and 22 of the housing 12. The first and innermost groove pair 32, 34 is a relatively wide groove and slideably receives therein from either open end the reflector 30. The second and intermediate groove pair 36, 38 is located forward of the innermost groove pair between the front edges 40, 42 of the housing and the first innermost groove pair 32, 34. Slideably received in the second intermediate groove pair 36, 38, also from either end of the housing, is a safety borosilicate glass lens 44. The lens 44 is retained in the second intermediate groove pair 36, 38 by a pair of channel shaped gaskets 46, 48 which slide into each groove, 36 and 38, and surround the opposing edges of the lens 44. As shown in FIGS. 1 and 2 the length of the lens 44 is less than the length of the housing 12 thereby defining at least one opening 50 into the interior of the housing 12. Preferably, the lens 44 is positioned centrally between the ends of the housing 12 creating a second opening 52 thereby defining a pair of openings 50, 52 at opposing ends of the lens 44 into the housing interior. Although not limited thereto, the principles of the present invention contemplate that a tungsten-halogen quartz lamp 54 is to be used in the fixture. These lamps generate considerable heat in operation and according to a very important aspect of the invention the pair of openings 50, 52 on either end of the lens provides for introduction and circulation of ambient air into and through the housing interior to cool the lamp 54 and reflector 30. Additional cooling is achieved by utilizing material for the housing 12 which has a high coeficient of thermal conductivity such as the extruded aluminum set out hereinabove. The housing is further provided with a plurality of grooves 56, 58, 60, 62 in the outer surface of the top wall 14 which increases surface area and heat dissipation from the housing 12 to the atmosphere. 
     As shown in FIGS. 1 and 2 the lamp 54 is mounted to the inner surface of one end cap 26 as described below between the lens 44 and the reflector 30 in a predetermined location relative to the reflector 30 so as to create a desired light pattern from the fixture 10. It can be seen that in the embodiment described herein, the lamp 54 is positioned above the principle longitudingal axis of the housing 12 and in close proximity to the upper portion of the reflector 30 and the top wall 14 of the housing 12. This location causes considerable heat to be concentrated at the top wall 14 which the grooves 62, 60, 58, 56 therein help to dissipate. 
     As stated, the reflector 30 is asymmetrically-shaped when viewed from the end. The asymmetrical cross sectional shape and elongated straight configuration creates an even, uniform, wide spread illumination pattern having sharp light cut-off at the top and bottom of the pattern. Additionally, as shown in FIGS. 1, 2, 4 and 5, the reflector 30 includes a blackened light absorbing portion along a pre-determined portion at the bottom thereof to prevent reflection of light from that portion of the reflector 30 back towards other portions of the reflector 30. This light absorbing portion further contributes to a light pattern having sharp cut-offs at the top and bottom thereof. It can be appreciated that the light pattern provides for cut-off of the light coincident with, for example, the interface between a ceiling and wall or any other straight interface between a pair of joining surfaces. 
     Referring principally to FIG. 6, each end cap 24, 26 is provided with a raised peripheral rim 64 complementary to the shape of the housing ends 20 and 22. Each end cap 24, 26 is removeably positioned across one of the respective open ends 22 and 20 with the peripheral rim 64 engaged over the top 14, back 18 and bottom walls 16 of the housing 12. A pair of stamped, generally rectangular shaped plates 66, 68 are affixed to the inner surface of each end cap 24, 26 with, for example, fasteners 70, 72 received in a pair of internally threaded bosses, not shown, cast into the end plates 66 and 68. The end plates 66, 68 are identical except that one, such as that designated 68 in FIG. 7, is provided with means for mounting a lamp socket 74 which holds and energizes the lamp 54. Each plate 66, 68 is provided with a pair of spaced apart retention tabs 76, 78 extending substantially parallel to the inner surface of the end plate 66, 68 and in spaced apart relationship therewith as shown best in FIGS. 7 and 10, the end of each plate 66, 68 adjacent the rear wall 18 defines a pair of stop surfaces 80, 82 which abut the respective ends such as the end 84 shown in FIG. 10, of the back wall 18 when the end caps 24, 26 are removed from the open ends 22, 20 of the housing 12 with the back wall 18 positioned between the tabs 76, 78 and inner surface of each end cap 24, 26, see FIG. 10. 
     Referring to FIG. 4 and 5, the back wall 18 is provided with a T-slot 86 which extends thereacross between the opposing ends 22, 20 of the housing 12. A strap like elongated bracket mounting plate 88 is slideably received in the slot 86 from either open end 22, 20 and is preferably affixed to the back wall 18 with a pair of fasteners 90, 92. Extending between each bracket mounting plate fastener 90, 92 or, if desired, some other connection point on the housing, and one of the retention tabs 76, 78 are a pair of springs 94, 96. It can be appreciated that with the end caps 24, 26 positioned against the housing 12 across the open ends 22, 20, the springs 94, 96 bias and hold the caps 24, 26 in place, thereby maintaining the housing 12 closed. It can also be appreciated that when the end caps 24, 26 are removed from the open ends 22, 20, as hereinabove described, and as shown best in FIG. 7, the springs 94, 96 bias the stop surfaces 80, 82 against the housing 12 ends which, with the retention tabs 76, 78, hold the end caps 24, 26 in the open position providing access the the housing 12 interior from either end 20, 22. According to a very important aspect of the invention, it can be appreciated that servicing of the components of the fixture 10 including lamp 54 replacement and removal and insertion of the reflector 30 and lens 44 is achieved from either open end 20, 22 by positioning either end cap 24, 26, or both, removed from their respective end 22, 20 of the housing 12. Reassembly is achieved by sliding the reflector 30 and lens 44 into their respective grooves 32, 34 and 36, 38 and repositioning the end cap or caps 24, 26 in the closed position. 
     Now, referring to FIG. 6, the fixture 10 is physically mounted and electrically connected to a track, not shown, of a track lighting system, also not shown in the drawings, with a novel mounting arrangement including the heretofore mentioned bracket mounting plate 88 to which up upstanding Y-shaped hanger 98 is affixed. The hanger 98 includes a pair of legs 100, 102 each of which is attached at one end to the plate 88. The hanger 98 is a two-piece member joined together at the junction of the legs 100, 102 to form a double thickness planar portion 104 at the free end thereof which double thickness tends to increase the strength of the mounting arrangement. Other constructions embodying the principles of the invention are possible including forming the Y-shaped hanger 98 from an elongated, one-piece strap, stamped or folded member to form the Y-shape and double thickness portion. 
     Rotationally attached to the planar portion 104 through a frictional attachment is an L-shaped mounting pad 106 to which an upstanding hollow decorative mounting stem 107 is affixed with at least one fastener 108. The mounting pad 106 to hanger 98 mounting is effected by a rivet or pin 112 extending through aligned clearance holes in the pad 106 and planar portion 104. A spring washer may be used between the pin and hanger to achieve additional frictional retention of the pad at selected angular positions relative to the hanger. The free end of the stem 107 is affixed to a track connector 120 which is well known in the art and which is adapted to electrically couple electrical leads 122, 124 which pass through the hollow stem to the electrical conductors within the track. The connector 120 also mechanically affixes the stem 107 to the track in wall known manner. Typically, the connector 120 is adapted to provide for rotation of the stem 107, and thus the fixture 10, in a plane lying parallel to the surface to which the track is mounted. 
     As shown in FIG. 1a, the stem 107 passes through a slot 126 provided in portions of the top 14 and back walls 18 of the housing 12 and connects to the pad 106 internally of the housing 12 providing for an esthetically pleasing appearance. Also, the slot 126 is adapted to provide for pivotal movement of the housing 12 through an angle of at least 90°, as shown in FIG. 1a, which provides sufficient movement to effect desired lighting pattern changes. 
     As shown best in FIG. 9, the top 14 and bottom walls 16 of the housing 12 are also provided with a third outermost pair of aligned grooves 128, 130 at the front of the housing. These grooves 128, 130 are configured to slideably receive an accessory item such as a shutter 132 shown in FIGS. 8 and 9 or, for example, a color filter or baffle to achieve interchangeable special lighting effects. 
     OPERATION 
     In use, the connector 120 is secured to the electrical track of the track lighting system in well known manner and the vertical angle of the fixture 10 is adjusted by pivoting the housing 12. Many lighting effects can be achieved, for example, to illuminate an object on the wall or to illuminate an entire wall from floor to ceiling. In such case, the sharp light cut-off at the top and bottom provided by the fixture 10 of the present invention limits the light to only the wall. The light cut-off provides for framing of an object to be illuminated. Special effects can be achieved by removing one end cap 24, preferably that cap 24 opposite the lamp socket 74, from the housing 12 and sliding an accessory item such as a filter, shutter or baffle into the outermost groove of the housing 12 and then replacing cap 24. It can be seen that the structure provides for fast, easy changing of accessory items as well as servicing of the lamp 54, lens 44 and reflector 30 when required by removal of the end cap or caps 24, 26. The end caps 24 or 26, when removed can be stored in an open position without having to be completely disconnected from the fixture 10 by engaging the stops 80, 82 on the plates 66, 68 to the end of the housing such that the springs 94, 96 and tabs 76, 78 cooperate to hold the caps 24, 26 in the open position. A housing 12 constructed according to the principles of the present invention is safe, easily serviced and allows novel lighting effects by providing sharp light cut off at the top and bottom of a uniform field of spread illumination. 
     Having described the preferred embodiment of the invention, those skilled in the art having the benefit of the description and the accompanying drawings can readily device other embodiments and modifications. Therefore, said embodiments and modifications are to be considered to be within the scope of the appended claims.