# Patent

## Title
In-grade light fixture

## Abstract

An in-grade light fixture comprises a light fixture housing arranged to be buried substantially below grade level. The light fixture housing has a light opening substantially at grade level and an optical chamber having a light source arranged within the optical chamber and the optical chamber arranged within the housing with light from the light source passing through the light opening. The fixture further comprises a plurality of housing openings and one or more enclosures, each of which is removably mounted to a respective one of the housing openings. The enclosures accept external power and generate power to energize the light source causing it to emit light. The optical chamber can also comprise an anti-condensation valve and an air passageway between the optical chamber and one of the enclosures form a vacuum in the optical chamber and vacuum during operation.

## Background
This application is a continuation-in-part from and claims the benefit of U.S. patent application Ser. No. 11/266,843 filed Nov. 4, 2005 now U.S. Pat. No. 7,553,042, which claims the benefit of provisional application Ser. No. 60/625,472 to Hagen, filed on Nov. 4, 2004.


BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to lighting fixtures and more particularly to in-grade lighting fixtures.
2. Description of the Related Art
Conventional in-ground or in-grade lighting fixtures are typically buried all or partially below ground level and include a light emitter that illuminates up from below ground level. They can be buried in the earth or covered by hardscape such as concrete, asphalt, wood, pavers, tile, etc. The fixtures are typically used to illuminate walls, columns, flags, trees, signs or a pathway.
One type of in-grade lighting fixture generally comprises a housing and lens made of glass or other rigid and transparent material that is attached to an opening in the top of a housing. The housing contains various components including the light emitter that is arranged to emit light through the lens and electrical components that are used to power and operate the light emitter. When the light fixture is installed in-grade, the housing is typically below ground level and the lens is left uncovered so light can shine up through it. The electrical components can include a power supply, power converters, transformers, and mounting hardware for the light emitter. To hold all of these components, the housing can extend relatively deep into the ground (i.e. 14 to 16 inches).
During installation of these types of light fixtures, a hole is typically dug for the housing, the housing is placed in the hole and the hole is back filled around the housing. Any hardscape is then installed around the lens, leaving the lens uncovered.
In-grade light fixtures can have an optical chamber that contains the light emitter (lamp), with the optical chamber arranged in the housing so that light from the lamp emits through an upper housing opening. One disadvantage of conventional optical chambers is that condensation can develop inside the chamber through the heating and cooling of the lamp. These types of fixtures also have ballasts that contain electronic components such as transformers and capacitors. These ballasts can also develop condensation during heating and cooling that can cause failure or reduced life of the components.
The most common problems resulting from water inside the housing include corrosion, electrical shorts, shortened life of the ballast (power converter) or transformer and shortened lamp life. In addition, water entry into the electrically sensitive areas can create risk of electrocution for those working on the housing.
In other conventional light fixtures one or more enclosures can be included inside the housing to hold electrical components, which can increase the overall size of the light fixture. Conventional light fixtures also do not provide flexibility in the placement of enclosures to allow the light fixture to be configured to meet space constraints during installation.
SUMMARY OF THE INVENTION
The present invention seeks to provide an improved in-grade light fixture. One embodiment of an in-grade light fixture according to the present invention comprises a light fixture housing arranged to be buried substantially below grade level. The light fixture housing has a light opening substantially at grade level and an optical chamber having a light source arranged within the chamber and the chamber arranged within the housing with light from the light source passing through the light opening. The fixture further comprises a plurality of housing openings and one or more enclosures, each of which is removably mounted to a respective one of the housing openings. The enclosures accept external power and generate power to energize the light source causing it to emit light.
These and other further features and advantages of the invention would be apparent to those skilled in the art from the following detailed description, taking together with the accompanying drawings, in which:



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top view of one embodiment of an in-grade light fixture according to the present invention;
FIG. 2 is a side elevation view of the in-grade light fixture in FIG. 1;
FIG. 3 is a perspective view of the in-grade light fixture in FIG. 1;
FIG. 4 is a perspective exploded view of the in-grade light fixture in FIG. 1;
FIG. 5 is a top view of the in-grade light fixture in FIG. 1 with the enclosures arranged differently in the enclosure openings;
FIG. 6 is a side elevation view of the in-grade light fixture shown in FIG. 5;
FIG. 7 is a top view of the in-grade light fixture in FIG. 1 with the enclosures arranged differently in the enclosure openings;
FIG. 8 is a side elevation view of the in-grade light fixture shown in FIG. 7;
FIG. 9 is still another top view of the in-grade light fixture of FIG. 1 with the enclosures arrange differently in the enclosure openings;
FIG. 10 is a side elevation view of the in-grade light fixture shown in FIG. 9;
FIG. 11 is a sectional view of the top section of one embodiment of an in-grade light fixture according to the present invention;
FIG. 12 is side view on another embodiment of an in-grade light fixture according to the present invention;
FIG. 13 is a top view of the light fixture shown in FIG. 12; and
FIG. 14 is a side view of another the light fixture shown in FIG. 13.



DESCRIPTION OF THE INVENTION
The present invention provides an improved light fixture, and although the features are described with reference to in-grade embodiments it is understood that the features can also be used in many other light fixtures pursuant to the present invention. It is also understood that the features and components of the light fixture embodiments described herein can be arranged in many different ways pursuant to the present invention.
FIGS. 1 through 10 show one embodiment of an in-grade lighting fixture 10 according to the present invention that is arranged to be smaller and easier to use compared to conventional in-grade fixtures. It is also arranged to provide greater flexibility in installation and to have greater reliability. As further described below, the fixture has features to prevent condensation in the optical cavity and transformer enclosure to optimize performance and increase the reliability of both. Further, the enclosures containing the ballast components can be mounted in different locations on the exterior of the fixture housing to allow the fixture 10 to be configured to best match the space available at a particular installation location. The fixture also prevents the collection of water in the upper section slot that can reduce reliability, particularly in installations where the temperature can be below freezing.
The lamp fixture 10 also comprises the inventive features of the lamp fixture in U.S. patent application Ser. No. 10/799,393, entitled “In-Grade Light Fixture With Leveling and Alignment Mechanisms, Installation Features and Anti-Condensation Valve,” the contents of which are incorporated herein by reference. Some of these features include a faceplate mechanism for adjusting the level and angle of the faceplate and for adjusting the orientation of the faceplate screw holes. Others include an optical chamber anti-condensation valve.
Others include a mechanism for holding the light fixture at a desired level in a hole during installation. For example the fixture 10 comprises a generally cylindrical housing 12 having an axial mounting shelf 2 located approximately at the housing's mid-section, that is used for conveniently and accurately mounting the lighting fixture 10 in a hole so that it is level and at the appropriate height. The shelf 2 is generally horizontal and has a plurality of holes 4. It is understood that the shelf can be arranged with many different numbers of holes spaced in different ways, with fixture 10 having four holes 4 equally spaced around the shelf. Each hole has one of four upwardly extending hole sleeve 5. The shelf 2 extends around the housing 12, although it is understood that the shelf can have interruptions.
The holes 4 and sleeves 5 have the same diameter and are sized to accept elongated stilts, such as standard PVC pipe. Alternative holes and sleeves can have different diameters to accept different sizes of PVC pipe or different elongated stilts, and the hole and sleeve cross-section can have different shapes such as square, rectangle, oval, etc. For example, the holes and sleeves could have a square cross-section to accept standard commercially available sizes of wood.
The PVC pipe can be mounted within each of the holes 4 using many different mounting methods, including but not limited to gluing, welding, clamping, or crimping. In a preferred mounting method each pipe is held in the sleeve hole 4 and sleeve 5 by a sleeve mounting screw. Each sleeve 5 can have a longitudinal crease on its outside surface to assist in turning a screw into the sleeve 5 and fix the sleeve 5 to PVC pipe inserted therein. The crease is designed to accept a standard “TEK screw”, although other screws can also be used. The screw can be turned partially through a respective sleeve 5 at the crease, which causes the sleeve 5 to bulge toward the PVC pipe and hold it in place. Alternatively, the screw can be turned through the sleeve 5 and into the PVC pipe to hold it in place.
In one method of using the mounting shelf 2 and PVC pipe according to the invention, the light fixture 10 is placed in a hole. Separate pieces of PVC pipe are then inserted into the holes 4 and sleeves, with each of the pipes being long enough that their lower end rests on the surface of the ground at the base of the housing 12 and their upper end extends through and above the top of its respective sleeve 104. The lower end of each of the PVC pipes is then forced into the ground, preferably by hammering on each pipe's upper end. The pipes should be pounded in far enough so that they can support the weight of the lighting fixture 10. The lighting fixture can then be slid up and down on the PVC pipes until it is at the desired height and angle. Tech screws can then be inserted into the sleeve creases to hold the light fixture 10 at its location so that the light fixture 10 is then held above the ground on the PVC pipes. The hole can then be backfilled and leveled around the protective cover and any desired hardscape can be installed.
It is understood that the mounting holes can be located in many different places on the fixture 10 beyond the shelf and can be arranged in many different ways with many different mounting features. The bottom surface of the shelf 2 can also comprise rebar clips that can be arranged to rest on rebar in those installations where rebar is used to reinforce the hardscape.
The shelf 2 also serves to stabilize the fixture 10 after the light is installed in its hole. After the hole is backfilled with an installation substrate (such as with soil, concrete, stone or other materials) the shelf 2 projects into the installation substrate. By projecting into to the installation substrate, the shelf helps anchor the fixture 10 in it installed position. This is particularly useful in “drive-over” installations where the fixture is installed in a location where pedestrians or vehicles travel over the fixture. The weight of pedestrian and vehicles can force the fixture down over time, such that its level is lower than desired and originally installed. The shelf 2 helps prevent this movement down by providing an axial anchor projecting into the substrate. In some situations the fixture 10 can also be forced up after installation, such as by earth movement, flooding, etc. The shelf 2 can also help to anchor the fixture 10 to prevent this upward movement.
The cylindrical housing 12 is divided into upper, middle, and lower sections 14, 16, and 18. The section can be made of many materials and composite materials, with a preferred material being rugged, watertight, and corrosion resistant. One suitable material is a high strength, thermo-formed polyester compound that is formed into the sections 14, 16, and 18 using known methods. The lower section 18 preferably comprises slots in its bottom surface to enable any water that enters the housing to drain out.
The fixture 10 also comprises an optical chamber 20 that is arranged within the housing by the optical chamber's axial lip 22 resting on the top surface of the upper section 14 such that essentially all the chamber 20 is within the housing 12. The optical chamber can be made of many different materials, with a suitable material being a metal.
The optical chamber 20 can be arranged in many different ways and can have many different shapes, but is preferably closed at bottom 21 and has an opening at its top 23 (best shown in FIG. 4). The enclosure bottom can have an electrical connector for supplying power to the optical chamber 20. A lamp (not shown) is mounted within the optical chamber 20 such that it emits light out the top opening of the chamber 20 when power is applied to it. Many different lamps can be used, with a suitable lamp being a commercially available 70 W Medium Base Metal Halide Lamp. Other optical chambers according to the present invention can house different types of emitters, including but not limited to light emitting diodes, lasers, fluorescent lights, etc., each of which can be arranged in many different ways within the chamber. The optical chamber 20 can also comprise a mounting system that allows the lamp to pivot to adjust the direction of lamp illumination without changing the position or angle of the chamber 20.
The lighting fixture 10 also comprises a junction box 24 attached at the exterior of the housing 12, and although it can be mounted in many different ways and in many different locations, in the embodiment shown it is mounted with the junction box 24 being substantially outside the housing at opening 25 of the housing's middle section 16. Power is supplied to the junction box 24 from an outside power source along known electrical conductors (not shown), and as is also known in the art, the electrical power for operating the lamps and light fixture components is typically brought to the lighting fixture 10 by wiring contained in an outer protective conduit line that attaches to the housing at a junction box 24. The wiring can be connected to the junction box using a quick disconnect connector having an anti-siphon valve. The junction box 24 provides a wiring compartment for electrically connecting the light fixture to the external supply of power provided by the electrical conductors.
The fixture 10 further comprises first and second exterior electrical enclosures 26, 28 that preferably hold the ballast electrical components, although in other embodiments they can hold other components. The enclosures are preferably mounted to the exterior of the housing's middle section 16 in much the same way as the junction box 24, with the enclosures substantially outside the middle section 16. The middle section 16 has three upper enclosure openings 30a, 30b, 30c each of which is sized such that one of the enclosures 26, 28 can be mounted to the outside of the housing at a respective one of the openings 30a, 30b, 30c. When less than three enclosures are used, such as in the embodiment shown having two enclosure 26, 28, one or more of the openings do not have an enclosure. For those, opening side blanking plate 32 can be inserted to cover the opening.
Each of the enclosures 26, 28 can be mounted to its respective one of the openings 30a, 30b, 30c in many different ways such as by screws, clamps, or bonding materials. In the embodiment shown, each of the enclosures 26, 28 has a ridge 31 sized to fit within a slot 33 in the openings to hold the particular enclosure in its opening. When the upper section 14 is mounted on the middle section 16, the enclosures 26, 28 and blanking plate 32 are fixed in their openings. Screws, clamps or bonding materials can also be used with the slot and lip arrangement to more securely mount the particular one of the enclosures 26, 28 within its opening and sealants or gaskets can be included at the openings to provide a watertight seal.
The housing's lower section 18 can also have first and second bottom enclosure openings 34a, 34b that are also sized to hold the first and second enclosures 26, 28. By including three middle section openings 30a, 30b, 30c and two bottom section openings 34a, 34b, the fixture 10 provides for flexibility in the arrangement of the enclosures to match the confines of an installation location. The fixture is provided with five openings each of which can have an enclosure, which allows for up to five enclosures to be used with the fixture 10, and when less than five are used, allows for the enclosures to be placed in different openings. It is understood that other embodiments of the fixture according to the invention can have more or fewer openings and the openings can be in many different locations. In one embodiment, for example, the fixture does not have bottom enclosure openings.
Referring to FIGS. 1-4, if space were a premium along the edge at the opening 30c during installation, a blanking plate can be installed in the opening 30c as shown and the first and second enclosures 26, 28 can be installed in openings 30a, 30b. This allows for installation of the fixture 10 without one of the enclosures 26, 28 projecting into the space adjacent to the opening 30c. Bottom blanking plates 38 can also be installed in the bottom openings 34a, 34b. 
Referring now to FIGS. 5 and 6, if space were a premium along the edge at opening 30a, a blanking plate 32 can be installed in opening 30a and the enclosures 26, 28 can be installed in openings 30b, 30c. Referring to FIGS. 7 and 8, if space is a premium along opening 30b, a blanking plate 32 can be installed in opening 30b and the enclosures 26, 28 can be installed in openings 30a, 30c. In the embodiments of FIGS. 5-8, bottom blanking plates (not shown) are also included in the lower sections bottom openings.
Referring now to FIGS. 9 and 10, when space is a premium adjacent to all or some of the openings, 30a, 30b, 30c, but is not as critical below the fixture 10, the enclosures 26, 28 can be installed in the bottom openings 34a, 34b (shown in FIG. 4). Blanking plates 32 can then be installed in each of the openings 30a, 30b, 30c. 
The lighting fixture 10 is generally arranged with two enclosures 26, 28 in those embodiments using magnetic light ignition known in the art. The first enclosure 26 can hold the starting circuit and a capacitor, while the second enclosure 28 holds the transformer. By separating the electronic components in this way heat from the transformer in the second enclosure 28 is less likely to impact the more heat sensitive components in the first enclosure 26.
In those embodiments utilizing electronic light ignition known in the art, the type/size of the electrical components is such that heat transferring from the transformer to the other electrical components is not as much of a concern. All the electronic components can be housed in a single enclosure that can be mounted in any one of the middle section openings 30a, 30b, 30c and bottom section openings 34a, 34b. Blanking plates would then be included in each of the other openings. In each of the embodiments described herein, the enclosures can include a potting material to help seal the components and to facilitate heat dissipation.
Referring again to the embodiment of FIGS. 1-10 having first and second enclosures 26, 28, power enters the housing 12 through wiring from the junction box 24, with the wires providing power to the first enclosure 26. Power from the first enclosure 26 is then provided to the second enclosure 28 where the transformer then provides the appropriate power signal to energize the lamp in the optical chamber 20. Power from the second enclosure 28 is provided to the optical chamber using known power conductors and connectors with the typical conductors being connected at the base of the optical chamber 20.
Referring now to FIG. 4, the fixture 10 can also have a tube 40 running between the optical chamber 20 and one or more of the enclosures. The tube can be arranged to allow conductors to run through it between the optical chamber and the enclosure, and the tube preferably would not collapse if a vacuum is created in the tube. As shown, the second enclosure 28 has a tube with power conductors running within the tube 40. The tube 40 is connected between the optical chamber 20 and second enclosure 28 using known connectors, with an air-tight seal between the tube and optical chamber 20 and enclosure 28 at the connection points. The tube 40 is also air tight, but is arranged such that air is allowed to pass between the optical chamber and cavity through the tube 40 while preventing air from escaping from the second enclosure 28, optical chamber 20, or tube 40 at the connection points. This arrangement allows for a vacuum to be created in the second enclosure 28 when a vacuum is created in the optical chamber 20 as described below. This vacuum reduces the formation of condensation in the second enclosure 28, which improves the light fixture's performance and reliability.
The optical chamber 20 comprises a valve 42 (shown in FIG. 4) that is fully described in U.S. patent application Ser. No. 10/799,393 referenced above. The valve 42 is designed and positioned to allow air to pass out of the optical chamber 20 when pressure builds up in the chamber 20, and to block ambient air from passing back into the chamber 20. When the chamber 20 is installed in the housing 12 and the faceplate mechanism is mounted in place over the opening of the chamber 20, a seal is created between the faceplate and the chamber 20 such that the inside of the chamber 20 is sealed from the ambient environment and the only way for air to pass out of the chamber 20 is through the valve 42. During operation of the fixture 10, air within the chamber 20 and the second enclosure 28 is heated, which causes the air to expand and air pressure to build within the chamber 20 and enclosure 28. As the pressure builds, air passes out of the valve 42.
When the fixture 10 is not operating, the air within the chamber 20 and enclosure 28 cools, but no air is allowed to pass back into the chamber 20 (or enclosure 28) through the valve 42. This results in the formation of a negative air pressure, or vacuum, within the chamber 20 and enclosure 28. This negative air pressure has the benefit of preventing condensation within the chamber 20 and enclosure 28 while not requiring the enclosure to have its own valve. It is understood that additional tubes can be included between the optical chamber 20 and the first enclosure 26, or the junction box 24. The enclosures 26, 28 and junction box 24 can also have their own anti condensation valve and air tight tubes can also run between them.
FIG. 11 shows a sectional view of the housing's upper section 14, with a faceplate 50 mounted over the opening in optical chamber and faceplate. As described in U.S. patent application Ser. No. 10/799,393 referenced above, the faceplate 50 is arranged to move up or down to align the angle of the faceplate 50. The housing's upper section 14 (or collar) has an groove 52 aligned with the lower edge of the faceplate 50, which allows for a greater range of movement down than if the upper section 14 had no groove 52. In previous light fixtures the groove was U-shaped such that water could collect in it and if this water froze, it could force the faceplate 50 out of the groove 52. To prevent this possibility, the upper section has been arranged such that the groove 52 is L-shaped and any water entering the groove 52 simply continues to run out and down the housing. In freezing conditions there is no water in the groove 52 to freeze.
FIGS. 12 through 14 show another embodiment of a light fixture 70 having many of the features as fixture 10 described above, including those of the lamp fixture in U.S. patent application Ser. No. 10/799,393, entitled “In-Grade Light Fixture With Leveling and Alignment Mechanisms, Installation Features and Anti-Condensation Valve,” The fixture 70 generally comprises a housing 72 having a “square” upper portion 74 and a cylindrical lower portion 76. The optical chamber (not shown) is mounted within the housing 72, much the same way as optical chamber 20 is arranged within the housing of fixture 10 described above. The upper portion 74 comprises a base 80 (shown in FIG. 14 being below the lower portion, but is part of upper portion 74) with bottom surface having a base hole 81 and four legs 82 extending up from the bottom surface. The lower cylindrical portion 76 is mounted in and affixed to the base 80 when the fixture 70 is assembled.
The upper portion 76 also comprises a cap 84 that is mounted to the legs 82 by screws 86, with the legs 82 providing separation between the base 80 and the cap 84. This separation provides four enclosure openings 88a-d with each of the openings defined by the base 80, adjacent legs 82 and the cap 84. Each of openings 88a-d can serve as a mounting location for a junction box 90 or electronic enclosure 91. In the openings not being used by a junction box 90 or electrical enclosures 91, blanking plates can be inserted in the unused ones of the openings 88a-d. The junction box 90 and electrical enclosures can then be electrically connected to an external source of power, to each other, and/or the remainder of the fixture 70 as described above.
The fixture 70 has a mounting arrangement similar to the mounting shelf 2 shown and described above. The fixture 70 has mounting holes 92 at the end of the legs and the holes 82 can have different shapes and sizes, but are preferably sized to accept standard sizes of PVC pipe. Each of the holes 92 also has a sleeve 94 similar to the sleeve 5 described above, and a PVC pipe can be mounted within the sleeve 94 by the different methods described above, including by a screw. When the fixture 70 is assembled, the holes 92, surrounding portions of the legs 82 and the edge of the cap 84 form a structure similar to the shelf 2 described above.
The fixture 70 also comprises rebar clips 96 that can be arranged to rest on rebar in those installations where rebar is used to reinforce the hardscape. The rebar clips 96 in this embodiment are arranged on the base 80, preferably on the bottom surface of the base 80 in the vicinity of the legs 82. By being on the bottom surface 80, the clips 96 can rest on rebar and be affixed to the rebar without interference from the junction box 90 or electronic enclosures.
The upper portion 74, and in particular the base 80, in combination with the cap 84 serves as a stability flange for the fixture 70. That is, the base 80 projects into the installation substrate to reinforce housing stability. As described above, this is particularly useful in fixtures subjected to pedestrian or vehicle traffic where downward force is applied to the fixture 70. The base 80, working as a stability flange, helps reduce downward movement of the housing under this force.
Although the present invention has been described in considerable detail with reference to certain preferred configurations thereof, other versions are possible. Therefore, the spirit and scope of the invention should not be limited to the preferred versions in the specification.

## Claims

1. An in-grade light fixture, comprising:
a light fixture housing arranged to be buried substantially below grade level, said light fixture housing having a light opening substantially at grade level;
an optical chamber having a light source arranged within said chamber and said chamber arranged within said housing with light from said light source passing through said light opening;
a plurality of housing openings; and
one or more enclosures, each of which is removably mounted to and interchangeable with a respective any one of said housing openings, said enclosures arranged to accept external power and to provide said power to said light source, causing it to emit light.

2. The fixture of claim 1, further comprising a device to project from said housing into an installation substrate to promote stability of said housing.

3. The fixture of claim 1, further comprising a stability flange to project outwardly from said housing into a surrounding installation substrate to reinforce housing height stability.

4. The fixture of claim 1, further comprising an axial mounting shelf projecting outwardly from said housing into the surroundings to reinforce fixture height stability.

5. The fixture of claim 1, further comprising a base projecting into an installation substrate to provide height stability under downward pressure.

6. The fixture of claim 4, further comprising mounting holes for holding extensions.

7. An in-grade light fixture, comprising:
a light fixture housing arranged to be buried substantially below grade level, said light fixture housing having a light opening substantially at grade level;
a junction box mounted to said housing;
a plurality of housing openings; and
one or more enclosures, each of said enclosures capable of being removably mounted to and interchangeable with a respective any one of each of said openings, said enclosures interconnected to accept an external power supply and generate an electrical signal to energize a light source.

8. The fixture of claim 7, further comprising a device to project from said housing into an installation substrate to promote stability of said housing.

9. The fixture of claim 7, further comprising a stability flange to project outwardly from said housing into the surrounding installation substrate to reinforce housing height stability.

10. The fixture of claim 7, further comprising an axial mounting shelf projecting outwardly from said housing into the surroundings to reinforce fixture height stability.

11. The fixture of claim 7, further comprising a base projecting into an installation substrate to provide height stability under downward pressure.