Luminaire

Abstract

Luminaire for indoor industrial use has an optical assembly having a diameter substantially greater than its height and adapted to be mounted at relatively low height above the floor. The optical assembly includes a dish shaped refractor sealed at its periphery to a reflector and a lamp mounted therein with its base down. The optical assembly is hingedly connected at one side to an upper ballast housing to enable the optical assembly to be swung down to provide access to its interior for servicing the lamp.

Description

The present invention relates to lighting fixtures, and particularly to luminaires of industrial indoor type having gaseous discharge lamps.

It is an object of the invention to provide an improved luminaire of the above type which has reduced overall height and is adapted to be mounted at a relatively low height above the floor while producing desirable light distribution thereon with a minimum of glare.

It is another object of the invention to provide a luminaire of the above type which affords ready access to the interior of its optical assembly for re-lamping and other servicing operations.

Still another object of the invention is to provide a luminaire of the above type which affords protection from electrical hazards during servicing operations.

Other objects and advantages will become apparent from the following description and the appended claims.

With the above objects in view, the present invention in one of its aspects relates to a luminaire comprising, in combination, a ballast housing containing electrical operating means, an optical assembly comprising a reflector and a refractor connected to each other at their peripheries with the refractor arranged below the reflector, the optical assembly being substantially greater in diameter than in height, a lamp having a base and mounted in the optical assembly with its base down, the optical assembly being hingedly connected to the ballast housing for movement between a closed operative position and an open inoperative position providing access to the lamp.

The invention will be better understood from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a view in elevation, partly broken away, of an industrial luminaire embodying the invention;

FIG. 2 is a similar view showing the luminaire with the optical assembly swung down from the ballast housing;

FIG. 3 is an enlarged detail view of the connection between the reflector and refractor of the optical assembly; and

FIG. 4 is an enlarged detail view of the hinge connection between the optical assembly and the ballast housing.

Referring now to the drawings, and particularly to FIG. 1, there is shown an industrial luminaire comprising a somewhat dome-shaped ballast housing 1 connected to and supported by a wire conduit 2, such as a metal pipe, and containing electrical operating components such as ballast transformer 3 and capacitor 4. Ballast housing 1 is formed with cooling fins 1a for radiating and dissipating heat generated therein by the electrical operating components. Suspended from ballast housing 1 below the open bottom thereof is optical assembly 5 comprising reflector 6 and refractor 7.

Reflector 6 is formed of a somewhat conical upper portion 6a open at its top and a lower outwardly flaring skirt portion 6b, with both reflector portions having reflecting flutes formed in the walls thereof. Refractor 7 is a shallow, somewhat dish-shaped transparent member having light control prisms 7a extending around the outer surface of its peripheral wall. In the optical assembly, as seen in FIG. 3, the lower rims of reflector skirt portion 6b mates with the upper flanged rim of refractor 7, and they are securely joined together in permanent sealed relation by suitable means, such as by forming the reflector rim into an annular channel 6c in which the annular flanged rim of refractor 7 is received and held.

Lamp 8 is arranged in optical assembly 5 with its base down and mounted in that position by bracket 10. As seen best in FIG. 2, bracket 10 is generally V-shaped and secured at its upper arms to opposite upper portions of reflector 6. The apex of bracket 10 as its bottom is formed with a seat 10a in which lamp socket 9 with support bracket 9a is received and suitably secured. In such arrangement, lamp socket 9 is located closely adjacent the inner surface of the bottom panel of refractor 7, and lamp 8 extends upwardly in the optical assembly. The light center LC of lamp 8 is thus arranged in the proper position as shown in FIG. 1 relative to reflector 6 and refractor 7 to provide the desired light distribution.

The optical system embodied in reflector 6 and refractor 7 is more fully described in co-pending application of Willis et al, Ser. No. 123,553, filed Mar. 12, 1971, and assigned to the same assignee as the present invention.

Optical assembly 5 is hingedly connected to the bottom of ballast housing 1 by means of hinge 11 (see FIG. 4) comprising pivot pin 11a secured to reflector 6 and bracket 11b secured to ballast housing 1 in which pin 11a is removably received for pivoting therein. On the opposite side of the optical assembly, latch 14 secured to ballast housing 1 and engageable with hook 15 on reflector 6 serves to detachably hold optical assembly 5 in closed operative position covering the bottom of ballast housing 1. In such closed position, annular bead portion 6d extending around the top of reflector 6 is urged into a complementary gasketed annular recess 1b at the bottom of ballast housing 1 for sealing engagement therewith.

When latch 14 is disengaged from hook 15 on the reflector, optical assembly 5 may be swung down as a unit about hinge 11 as shown in FIG. 2, so as to provide access to the interior of reflector 6 for relamping or other service operations. While only one latch 14 is shown, it will be understood that in a usual case a plurality of such latches and co-acting hooks are arranged circumferentially spaced around the unit.

A seperable electrical connection of lamp 8 to the electrical operating components 3, 4 in ballast housing 1 is provided by means of electrical plug 16 secured within the upper portion of reflector 6 by means of an extension of bracket 10 and electrical receptacle 17 secured within the adjacent lower portion of ballast housing 1. In the closed portion of optical assembly 5 as seen in FIG. 1, plug 16 is in operable connection with receptacle 17, these parts being respectively electrically connected to lamp 8 and the ballast operating components by suitable electrical leads (not shown). Lowering of optical assembly 5 as shown in FIG. 2 thus automatically disconnects lamp 8 from the electrical supply, and raising optical assembly 5 to operative position automatically re-connects the lamp 8 for operation.

A removable cover plate 18 is arranged across the interior of ballast housing 1 to separate and seal off the compartment containing electrical ballast components 3, 4 from the interior of optical assembly 5 and thereby minimize passage of electrical heat and undesirable gases emanating from the ballast components to the optical assembly. Also such an arrangement prevents inadvertent contact by service personnel with the electrical components in ballast housing 1 during servicing operations.

Arranged below cover plate 18 and secured thereto is accessory reflector 19 which reflects downwardly light incident thereon from lamp 8 as disclosed in the aforementioned co-pending application.

In a typical luminaire constructed in accordance with the invention, the overall diameter of optical assembly 5 at the junction of reflector 6 and refractor 7 is about 31 inches, the overall height of the unit including ballast housing 1 and optical assembly 5 is about 21 inches, and the height of the optical assembly 5 is about 12 inches with the height of refractor 7 being only about 4 inches. Thus, the overall diameter of the optical assembly is substantially greater than the overall height of the entire unit and more than twice the height of the optical assembly. Because of the relatively large size of the refractor used in such a luminaire, it would usually be made of a synthetic plastic material such as an acrylic resin. Such a material is subject to discoloration if exposed to excessive heat due to close proximity to the lamp. By arranging lamp 8 with its base down in accordance with the invention, adequate spacing is provided between refractor 6 and the relatively hotter bulb portion of lamp 8 while still utilizing the space adjacent refractor 6 for the cooler lamp base and socket member 9. A further advantage in this arrangement is that the height of the ballast housing can be reduced since it need not accommodate the lamp socket, which in a base-up arrangement would have to be placed within the ballast housing so that the light center of lamp 8 can be correctly located at the proper optical position relative to the reflector flutes and the refractor prisms 7a, as more fully disclosed herein. Such proper positioning of the light center of lamp 8 is necessary to provide the desired distribution of light on the floor to be lighted as well as to avoid undue glare from the luminaire. In addition, the relatively low profile of the luminaire thus achieved makes it feasible to use the luminaire in areas having relatively low ceilings.

While the present invention has been described with reference to particular embodiments thereof, it will be understood that numerous modifications may be made by those skilled in the art without actually departing from the scope of the invention. Therefore, the appended claims are intended to cover all such equivalent variations as come within the true spirit and scope of the invention.

Claims

What we claim as new and desire to secure by letters Patent of the United States is:

1. A luminaire comprising, in combination, a ballast housing containing electrical operating means, an optical assembly comprising a reflector having an open bottom and a dish-shaped refractor having an open top, said reflector and said refractor being connected to each other at their peripheries with said refractor arranged below and closing the bottom of said reflector, said optical assembly being substantially greater in diameter than in height, a lamp having a base and mounted in said optical assembly with its base down, said optical assembly being detachably connected to said ballast housing for movement between a closed operative position against said ballast housing and an open inoperative position spaced from said ballast housing for providing access to the interior of said optical assembly.

2. A luminaire as defined in claim 1, said lamp being elongated and being arranged substantially entirely within said optical assembly.

3. A luminaire as defined in claim 2, bracket means secured within said optical assembly having a support portion arranged adjacent said refractor, and a lamp socket arranged in said socket support portion for receiving said lamp base.

4. A luminaire as defined in claim 1, the height of said reflector being about twice the height of said refractor.

5. A luminaire as defined in claim 1, the overall diameter of said optical assembly being substantially greater than the overall height of the combined ballast housing and optical assembly in operative position.

6. A luminaire as defined in claim 1, including hinge means at one side of said optical assembly for swingably connecting the same to said ballast housing, and latch means circumferentially spaced from said hinge means for detachably connecting said optical assembly to said ballast housing.

7. A luminaire as defined in claim 3, said bracket means comprising a generally V-shaped member having opposite upper arm portions and a lower apex portion, said bracket member being connected at its upper arm portions to the upper portion of said reflector, said lower apex portion being formed with a seat for receiving said lamp socket.

8. A luminaire as defined in claim 1, said refractor being composed of a light-transmitting synthetic resin material.

9. A luminaire as defined in claim 1, including separable electrical connecting means on adjacent portions of said optical assembly and said ballast housing for automatically electrically connecting and dis-connecting said lamp and said electrical operating means upon movement of said optical assembly into operative and inoperative positions, respectively.

10. A luminaire as defined in claim 1, said reflector and said refractor having mating peripheral rim portions and being joined together at said rim portions in permanent sealed relation.