This invention relates to track lighting and more particularly to a high intensity lighting fixture with an asymmetric output profile suitable for illuminating the surface of a race track.
Conventional high intensity lighting fixtures comprise are discharge lamps mounted in parabolic reflectors to create a securely symmetric output profile. Hoods, shields, and other devices to modify the output profile are known.
Race track lighting comprises high intensity fixtures mounted in multiples on high poles around fee perimeter of the track in much the same manner as one finds in football stadium lighting. While these systems may provide adequate lighting of the track surface for racing purposes, they do not take into account the special needs associated with televised night racing nor do they address the problems associated with the projection of high-intensity, divergent light beams into the direction of oncoming traffic.
An alternative system places mirrors along the infield side of the track and light fixtures, arranged in multiples on poles on fee grandstand, side directing light onto the mirrors which is thereafter reflected onto the track, see U.S. Pat. No. 5,343,374.
According to one aspect of the invention, there is provided a lighting fixture providing an asymmetric output profile characterized by a strong cut off in one lateral direction and divergent light in the other direction. Such a fixture is particularly suitable for race track lighting and includes a housing having a lateral axis of symmetry and a reflective inner surface. The term “lateral axis” is intended to mean that the axis of symmetry is cross-wise to the direction of transmitted light. An elongate high-intensity lamp is mounted in the housing with its are axis corresponding essentially with the axis of symmetry. The fixture further comprises an angled reflective side plate disposed in the housing to produce a laterally divergent light output from one side of the fixture.
In the preferred form, the fixture former comprises an elongate blocker plate which is mounted in front of and in spaced relationship to the high intensity lamp so as to essentially prevent the projection of uncontrolled direct light from the fixture; i.e. substantially all of the light coming from the fixture is first reflected off of a surface, of the reflective housing interior and/or the kicker plate.
In the preferred form, the fixtures are further provided with mounting brackets which permit adjustment of the pitch angle of the housing to accommodate different slopes or bank angles of the track at different locations. The housing is preferably configured with, a visor portion to limit upwardly divergent light therefrom. The visor may be integral or add-on.
In another aspect, the invention is a lighting system for race tracks having racing surfaces with a predetermined direction of traffic flow, and a primary viewing side wherein the system comprises groups of high intensity lighting fixtures preferably arranged opposite the primary viewing side of the track at relatively low altitudes and at spaced intervals so as to direct light onto the racing surface. Each of the fixtures in the system is arranged to provide a strong unilateral cut off which prevents the projection of light against traffic flow; i.e., into the eyes of drivers in oncoming traffic, but further provides a divergent projection of light in the direction of traffic flow so as to blend the light from one fixture with the light from another adjacent fixture thereby preferably creating a relatively uniform light level along the track. While the preferred fixture mounting location is opposite the primary viewing or grandstand side of the track, at any given location the fixtures may be on either side of the track as best suits other factors such as banking of the track in the lighted area.
The features and advantages of die invention will be best understood from a reading of the following specification which describes illustrative embodiments thereof.
In accordance with the invention and as shown in
Referring now to
The housing 24 is provided with opposite, parallel interior end walls 30 and 32 and a double-ended high intensity metal halide lamp 34 whose are axis coincides essentially with the axis of symmetry or focal axis of the fixture 24 as best shown in
The housing 24 is provided with a lower cabinet portion 40 which houses components such as ballast 42 and other common and conventional components. A mounting bracket 44 includes adjustable pivots 46. A pin 48 which travels in a slot 50 to permit adjustments of the pitch angle of the fixture according to the degree of bank and the location of the fixture 20A relative to the surface of the track 10. The fixture housing 24 is preferably be equipped with automatic cut off switch (not shown) to cut power to the lamp 34 in the event the hinged back 27 is opened or the glass cover 53 breaks.
The lamp 34 is preferably a metal halide lamp with wattage in the range of about 1,000 to 2,000 watts providing a bright white light suitable, for televised night racing. The strong cut-off in the direction of oncoming traffic prevents light from being inadvertently projected into the eyes of drivers and the divergent light in the direction of traffic flow causes tight from one fixture to be blended with the light from an adjacent fixture in the grouping shown in
Mounted in front of and spaced from the lamp 34 is an elongate, curved-surface blocker plate 52 made, for example, of aluminum to prevent direct light from coming out of the fixture 20; i.e., light which could normally come directly out the lamp 34 without first encountering a reflective surface of housing 24 hits the curved surface of plate 52 and is directed back. Into the housing 24. Therefore, substantially all light coming from fixture 20 is “controlled” in the sense that it is reflected off of an interior surface of reflector surface 26 or plate 36. The width of the plate 52 is a function of the size of lamp 34 and the spacing between the lamp 34 and plate 52.
It will be understood that additional fixtures 20 are arranged at other positions on the track 10 and that not all of the fixtures are necessarily provided with all of the accessories and features described with respect to the fixture 20. Therefore the phrase “each, of said fixtures” as used in the specification, and claims of this document refers to all of the fixtures in a group such as those shown at 20 in