Abstract:
The recessed wall-mounted light fixture assembly has a hollow mounting sleeve which is inserted horizontally in the wall, a lamp housing for enclosing and retaining a lamp, where the lamp housing is adapted to slide and rotate within the mounting sleeve, a face plate with a hood attached to the housing for directing light downward and preventing direct view of the lamp and a lens disposed within the face plate. The lamp is plugged into a socket mounted on a bracket that provides upward and downward adjustability. The lens has two different sections: an upper section which is frosted to diffuse light and a lower section that is clear for maximum transmission of light.

Description:
FIELD OF THE INVENTION 
     The invention is directed generally to an electrical light fixture, and more particularly, to a recessed light fixture which is wall-mounted to provide down-lighting. 
     BACKGROUND 
     Recessed wall-mounted light fixtures are commonly used in environmental lighting systems to illuminate walking surfaces adjacent a vertical surface. Such fixtures can be positioned to enhance safety in dark or shadowed areas and are particularly helpful for use near stairs or uneven surfaces where a pedestrian might be unaware of a step-off or edge that can trip him or her. Stairs and other uneven surfaces tend to create shadows when a light source is above the viewer&#39;s eye level shining down on the walking surface. These shadows can interfere with depth perception, creating a misimpression as to the depth of the step, which causes the pedestrian to incorrectly place his or her foot, resulting in a stumble or fall. This problem can be exacerbated by placing a bright light at a height that can temporarily blind the person as he or she looks upward while ascending the stairs. 
     A solution to the foregoing problem is provided by positioning recessed fixtures in the vertical wall at a height above the walking surface but well below the viewer&#39;s eye level. However, a disadvantage of such an installation is that, because of the relatively short distance between the light source and the illuminated surface, the beam spread is limited and a number of fixtures are needed to illuminate an entire surface such as a flight of stairs. Installation of a large number of fixtures can be problematic, particularly in a brick, concrete or stone wall. In addition, typical wall-mounted lights have a metal mounting box that is cast or permanently affixed into the wall. These metal boxes are primarily formed from steel and aluminum which can corrode from alkali that leaches out of the concrete or mortar. If the fixture fails and needs to be replaced, the box must be chipped out of the concrete. 
     Another drawback of existing wall-mounted fixtures is that the light source, i.e., the lamp within the fixture, is positioned at a fixed height and depth within the fixture, such that there is no provision made for variation of the beam spread and projection distance to optimize light distribution. 
     The need remains for a recessed wall-mounted light fixture that is easily installed and removed, resistant to corrosion and adjustable to optimize light distribution. The present invention is directed to such a need. 
     SUMMARY OF THE INVENTION 
     In an exemplary embodiment, a recessed light fixture assembly comprises a hollow mounting sleeve, a lamp housing for enclosing and retaining a lamp, wherein the lamp housing is adapted to slide and rotate within the mounting sleeve for installation and adjustment, a face plate with a hood attached to the housing for directing light downward and preventing direct view of the lamp and a lens disposed within the face plate. 
     The mounting sleeve is a cylinder formed from a plastic, polyvinyl-chloride (PVC) or similar material that can be installed into a wall during construction, or inserted into a bore formed in the wall post-construction. The lamp housing is cylindrical with an outer diameter adapted to closely and slidably fit within the inner diameter of the sleeve. The lamp housing can be adjusted relative to the sleeve along two axes. A first adjustment is along the axis of the sleeve, allowing the depth of the fixture to be adjusted so that the face plate abuts the outer wall surface. A second adjustment is axial rotation. The housing rotates freely within the sleeve to allow the installer to precisely set the level point of the fixture to ensure symmetrical light distribution. 
     In a preferred embodiment, a waterproof connection is disposed at the internal end of the housing to permit electrical connection to the socket within the housing. The socket is mounted on a slidable bracket which allows the socket to be shifted vertically along a plane running perpendicular to the axis of the housing. This adjustment allows the beam length and spread to be varied for use in different areas of illumination, i.e., in either large or small areas. The adjustment also provides means for glare control by shifting the lamp upward into a position that is fully shielded by the hood for reduced glare. 
     The face plate incorporates a hood, or brow, which extends outward to overhang the lens opening to keep the light source from direct view at standing eye level. The face plate has an annular flange that inserts into the open end of the housing where it is held in place by compression created by two O-rings and optional set screws. The O-rings allow the face plate to be rotated axially relative to the housing while still maintaining a water-tight housing. 
     In a preferred embodiment, the lens is formed from tempered glass, the upper half of which is frosted to reduce hard shadow patterns by producing diffuse light for projection onto the area directly around the fixture. The lower half of the lens is clear to provide long light projection with maximum light transmission at a lower level that is less likely to be directly visible to a pedestrian walking in the vicinity. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the present invention and, together with the description, disclose the principles of the invention, wherein: 
     FIG. 1 is an exploded perspective view of the recessed wall-mounted light fixture with the mounting sleeve; 
     FIG. 2 is a top plan view of the light fixture with the mounting sleeve; 
     FIG. 3 is a cross-sectional view taken along line  3 — 3  of FIG. 2; 
     FIG. 4 is a plan view of the face plate looking from the interior of the housing outward; 
     FIG. 5 is a front plan view of a bracket for adjusting socket and lamp position; and 
     FIG. 6 is a perspective view of the light fixture and mounting sleeve positioned within a portion of a wall. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in FIG. 1, light fixture  10  comprises a cylindrical housing  12  for retaining a light source  13  and face plate  14  for sealing the housing  12  and retaining a lens  16  through which light passes out of the fixture and onto the surface to be illuminated. Light fixture  10  is mounted in a vertical wall by sliding cylindrical housing  12  into a mounting sleeve  20  which was pre-mounted into the wall, either upon original construction or by boring an appropriate opening into an existing wall. 
     Mounting sleeve  20  is a plastic tube or pipe that is installed so that it extends horizontally, perpendicular to the plane of the wall surface. Preferably, sleeve  20  is PVC (polyvinylchloride) conduit or similar tubing. Conventional, commercially available PVC tubing, e.g., Schedule  40  PVC pipe, is suitable. Most preferably, the sleeve material conforms to Underwriter&#39;s Laboratory VO fire-rating, such as a fire retardant plastic or metal. Exemplary dimensions for sleeve  20  are approximately 51 mm (2 inches) I.D. (PVC Schedule  40  Nominal 2 inch) by 178 mm (7 inches) long. The diameter is selected to closely fit the exterior of housing  12  while still allowing the housing to be easily rotated and moved axially within sleeve  20 . The length of sleeve  20  is selected to provide space behind the housing  12  for excess wiring or cable so that the housing can be removed from the sleeve to provide access to the connector  18  at the back of the fixture. For installation, an excess length of sleeve tubing can be installed in the wall during construction, then the portion of the tube extending beyond the wall surface can be cut flush with the wall after any coatings or finishes, e.g., stucco, have been applied. 
     Housing  12  has a cylindrical body with dimensions adapted to closely fit within sleeve  20  in such a manner that allows the light fixture to be manipulated by rotation or sliding in an axial direction. An exemplary length for housing  12  is on the order of 80 mm 13.1 inches), with an outer diameter of 50 mm (2 inches). Housing  12  may be formed from metal such as brass, steel, aluminum or other appropriate metal, or from a fire resistant, heat tolerant plastic. Housing  12  has two chambers formed therein. Referring to FIG. 3, a first chamber  15 , which is located in the forward portion of the housing extends approximately halfway down the length of the housing, providing a space within which lamp  13  is retained. A second chamber  17  begins at annular edge  19 , extending to the rearward portion of the housing. Second chamber  17  retains the back end of the socket  22 , providing sufficient room to allow the position of the socket  22  to be moved in a plane parallel to the axis of the housing  12  and provides access for connection of the socket to. electrical conductors and/or connectors. Bore  24  is formed through the back end of housing  12  is dimensioned for insertion and retention of watertight connector  18 . Connector  18  can be pressed into bore  24  to create an interference fit, or preferably, bore  24  can be threaded to accept a standard threaded connector, e.g., a NPT ⅜″ connector such as is available from Heyco Products (Toms River, N.J.), or similar commercially-available liquid tight connectors. Cable  26  is electrically connected to a low voltage transformer (not shown) to provide voltage for operating lamp  13 . 
     Lamp  13 , shown in FIG. 3 with a built-in reflector, is a conventional halogen lamp for use in low voltage lighting systems. In the preferred embodiment, lamp  13  is a MR 8  type lamp which is available from a large number lamp manufacturers. Socket  22  is a conventional plastic socket that is also commercially-available from a number of sources. For example, appropriate sockets are available from BJB of Amsberg, Germany. Socket  22  is retained by bracket  30 , the details of which are illustrated in FIG. 5, which is discussed below. 
     Bracket  30  is adapted for attachment to edge  19  by way of one or more screws  32  which pass through a corresponding elongated slot  34  and into a threaded bore formed in edge  19 . The position of the bracket  30  within the housing can be adjusted by loosening screws  32  and sliding the bracket up or down along slots  34 . Once the desired location is achieved, the screws are re-tightened. Notches  36  that are cut through the bracket  30  define a bracket center section  38  which is bent along line  39  at a non-zero angle relative to the plane of edge  19 . In a preferred embodiment, bracket  30  is formed from metal such as steel or aluminum and powder coated to protect against corrosion in the event moisture is able to enter the housing. Selection of other appropriate materials and coatings will be apparent to those of skill in the art. As shown in FIG. 3, the angle of bracket center section  38  causes lamp  13  to be directed outward and slightly downward. By adjusting bracket  30  upward relative to the center axis, the lamp  13  is positioned so that is covered to a greater degree by hood  40 , which may be appropriate to reduce glare. Such adjustment also reduces the distance that light is projected from the fixture, directing a greater amount of light close to the fixture. This provides helps prevent glare when illuminating walkways or stairs with significant elevation changes. Adjustment of bracket  30  to a lower position relative to the center axis of the fixture causes light to be projected at a greater distance from the fixture. 
     Referring to FIGS. 3 and 4, face plate  14  has a hood  40  formed on the upper portion of its exterior which shields the lamp so that light does not shine upward into the eyes of a pedestrian who is passing by or walking towards the fixture. An exemplary diameter for face plate  14  that can be used in combination with previously described exemplary dimensions for housing  12  and sleeve  20  is 76 mm (3 inches). Hood  40  extends approximately halfway or more down face plate  14 . On the interior of face plate  14  is formed an annular flange  46  which has an outer diameter adapted to closely fit within chamber  17 . At least one O-ring seat is formed in flange  46  for retaining O-ring  48  so that, when flange  46  is inserted into chamber  17 , a watertight seal is created. In the preferred embodiment that is illustrated, two O-ring seats and two O-rings  48  are provided. Face plate  14  can be rotated axially relative to housing  12  and can be detached from housing  12  by overcoming the frictional resistance created by the O-rings  48  against the inner surface of chamber  17 . In a preferred embodiment, one or more set screws may be inserted into bores formed in the sidewall of housing  12  to prevent rotation of face plate  14  once the desired adjustments have been made. If additional adjustment is required, or when the lamp needs to be changed, the set screws are loosened to allow face plate  14  to be pulled away from or rotated relative to housing  12 . 
     Although face plate  14  is illustrated with a circular shape, other shapes, such as ovals, squares, rectangles or other polygons, can be used as long as flange  46  is cylindrical in shape for insertion into housing  12 . Face plate  14  may be formed from metal, preferably the same metal used to form housing  12 . Examples of appropriate metals include brass, aluminum that is anodized, powder coated or otherwise treated for corrosion resistance, steel, including stainless steel, etc. 
     A semi-circular opening  44  is formed below hood  40  in face plate  14  to permit light to escape from housing  12 . A circular lens  16  disposed within flange  46  against lip  42  covers opening  44 , fully enclosing lamp  13  within housing  12 . Lens  16  is attached to lip  42  using an appropriate adhesive to create a watertight seal. 
     Lens  16  is formed from tempered glass, quartz, or other transparent material suitable for use in light fixtures. In the preferred embodiment, the lens  16  has a bi-focal configuration. The upper portion  50  of lens  16  is treated to create a frosted surface which reduces hard shadows by scattering the light onto the area directly around the fixture. 
     Alternative means for diffusing light may be used and will be readily apparent to one of skill in the art. The frosted upper portion  50  of lens  16  is capable of scattering light 180° and therefore is positioned so that it is completely behind hood  40  to avoid the possibility of glare resulting from direct view. The lower portion  52  of lens  16  is clear to allow long light projection and high light transmission. Adjustment of the position of bracket  30  adjusts the relative fractions of light that are transmitted through the upper versus the lower lens surfaces. 
     FIG. 6 illustrates a light fixture  10  according to the present invention positioned within a cinderblock  60  with optional connection schemes. The first optional connection scheme involves the formation of openings through the sides of sleeve  20  for coupling to electrical conduits  62  through which connection to a voltage source is made. The use of the plastic or PVC tube makes it quite easy to drill appropriate openings for such an installation. The second option for connection is made by feeding wires  63  out of the back end of the housing  12  and sleeve  20 , through conduit  64  and out the back side of cinderblock  60  where connection is made to appropriate cable  66 . Both connection schemes can be provided for during construction of the wall by positioning the sleeve and conduits. Then, after the wall is completed, the light fixture  10  can be connected to cable that is inserted into the selected conduit and adjusted as needed. 
     Light fixture  10  provides the installer with flexibility to optimize the illumination. The free rotation of the fixture within sleeve  20  allows the installer to precisely set the level point of the housing. This is critical to ensure symmetrical light distribution. If the fixture is adjusted to emit a narrow beam spread, the fixture can project light about 10 meters or more. If the rotational adjustment of any wall light fixture is off by even a few degrees, it can dramatically affect the light distribution over distance, thereby reducing performance. For example, on very wide stairways, this could result in dark areas which can present in a pedestrian hazard. The light fixture described herein overcomes such problems and provides several other means for optimizing the illumination produced by a wall light. 
     While various embodiments of this invention have been described above, these descriptions are given for purposes of illustration and explanation. Variations, changes, modifications and departures from the systems and methods disclosed above may be adopted without departure from the spirit and scope of this invention.