Illumination – Light source and modifier – With sealing means or artificial atmosphere
Reexamination Certificate
2002-03-04
2004-10-05
Sember, Thomas M. (Department: 2875)
Illumination
Light source and modifier
With sealing means or artificial atmosphere
C362S350000, C362S277000, C362S280000
Reexamination Certificate
active
06799869
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a light fixture for use in low voltage outdoor lighting systems and more specifically to a down light fixture which is less susceptible to the effects of oxidation and corrosion.
BACKGROUND OF THE INVENTION
Environmental lighting, particularly outdoor lighting, is well known in commercial or public settings, such as parks and schools. Such lighting is also popular in residential applications, both to enhance the appearance and safety of the outdoor area and for security, to illuminate dark areas around a building or in a yard which may provide hiding places and unobserved entry points for intruders.
Landscape and outdoor lighting systems include one or more lighting fixtures which are connected to either a 12 V transformer or a standard 120 VAC line. Some lighting fixtures enclose a halogen or conventional bulb within a housing, and include a reflector assembly having a lens or window. These fixtures may be used for highlighting features such as trees or statues., i.e., up-lighting, or for path lighting. Other fixtures, used almost exclusively in down-lighting applications, may be open, with the lamp inserted into a socket within a shell or cowl that has its open end directed toward the ground. These fixtures tend to be used in larger quantities within a lighting system since they are typically less expensive than the closed fixtures and are capable of washing large expanses of open area with glare-free light, e.g., pathways, driveways, patios, and for perimeter lighting.
The open fixtures often have a cowl shaped in the form of a bell, half-shell, cone, tulip, or other bell-shaped flower that surrounds the lamp except for the lower end of the cowl from which the light emanates. In addition to preventing escape of light in an upward direction, the inner surface of the cowl acts as a reflector to optimize the amount of light directed toward the desired target area. However, because it is open to the elements, the inner surface of the cowl can become coated with a layer of dust and dirt following repeated exposure to moisture, enhancing corrosion and diminishing the reflectivity of the surface. Further, if the cowl is formed from an uncoated metal such as copper or brass, as commonly used in higher end fixtures, the inner surface of the cowl oxidizes, reducing reflectivity.
One method that has been used to overcome or minimize the effects of build-up and/or oxidation is to treat the inner surface of the cowl by coating it with a white paint or powder coating to produce a porcelain-like white finish, the latter providing a superior finish that is far more durable. However, in most cases, where only the inner surface is to be coated, the rest of the cowl must be masked or otherwise protected to prevent overspray from depositing on the outer surface. Then, after the masking step, the outer surface must be hand buffed to remove any residual markings and to ensure uniformity of the finish, thus introducing additional steps into the manufacturing process that result in the product being more costly.
It would be desirable to provide a light fixture that is attractive, easy to manufacture and provides a reflective surface that is not easily degraded by corrosion or oxidation. The problems and deficiencies are clearly felt in the art and are solved by the present invention in the manner described below.
SUMMARY OF THE INVENTION
It is an advantage of the present invention to provide a light fixture which has a cowl with a high quality reflective inner surface without requiring additional manufacturing steps to protect the exterior finish.
It is a further advantage of the present invention to provide a light fixture with improved resistance to degradation by corrosion and oxidation of the materials of which the fixture is made.
Another advantage of the present invention is to provide a light fixture which protects the lamp base and socket against exposure to the elements and intrusion by foreign objects.
In an exemplary embodiment, the light fixture comprises a spring-blased socket and a lamp retained within a base portion of a cowl disposed at an end of a goose-necked stem through which are passed wires for providing electrical connection between the socket and a power supply. The cowl is generally bell-shaped with a cylindrical base and a flared skirt, but may be any shape having a cavity for retaining the lamp and socket and an open and perhaps partially flared bottom. A collar having a profile closely matching at least a portion of the inner profile of the cowl has an opening at its center through which the base of the lamp passes. The collar, which in the preferred embodiment is formed from aluminum, is coated with a reflective (white) coating and is dimensioned so that light emitted from the lamp is reflected outward away from the fixture. The preferred coating is powder coating. A resilient O-ring is disposed around the base portion of the lamp so that when the lamp base is fastened within the socket, the O-ring presses against the collar, pressing it against the inner surface of the cowl. A metal connector formed preferably from brass can be used to connect the cowl to the stem to reinforce the joint. The stem typically has a threaded fitting at its distal end allowing connection to a riser pipe or ground spike.
The collar provides a reflector which will not degrade even as the material of which the cowl is made oxidizes and, while it is not completely watertight, it provides a barrier to entry of moisture, debris, spiders and insects that often collect within the inner cavities of open ended light fixtures. In an alternate embodiment the outer edges of the collar can have a resilient bead formed from silicone or a similar material so that the bead is compressed between the collar and inner surface of the cowl to enhance the fixture's moisture resistance.
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Procopio Cory Hargreaves & Savitch LLP
Sawhney Hargobind S.
Sember Thomas M.
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