Lighting fixture

May 12, 1970 r. g. blaisdell et al 3,511,984

LIGHTING FIXTURE Filed Dec. 27, 1967 2 Sheets-Sheet 1

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FIG. I

INVENTORS

RONALD G. BLAISDELL

HENDRIK A. J. de VOS

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BY

3,511,984

R. G. BLAISDELL ET AL

LIGHTING FIXTURE

May 12, 1970

Filed Dec. 27, 1967

Sheets-Sheet 2

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FIG. 2

INVENTORS

RONALD G. BLAISDELL

HENDRIK A. J. de V0S

ATTORNEY'

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BY

3,511,984

Patented May 12, 1970

United States Patent Office

3,511,984 LIGHTING FIXTURE Ronald G. Blaisdell, Saugus, and Hendrik A. J. de Vos, Wenham, Mass., assignors to Sylvania Electric Products Inc., a corporation of Delaware

Filed Dec. 27,1967, Ser. No. 693,902 Int. CI. F21v 7/00; F21s 1/02

U.S. Cl. 240—44.1 4 Claims

ABSTRACT OF THE DISCLOSURE

A luminaire for lamps of the metal vapor type in which an adapter ring may be interposed between the housing and the spider as a means for adjusting the relative location of the light center of the lamp with respect to the reflector whereby different light distribution patterns are obtained.

This invention relates to luminaires and more particularly to lighting fixtures employing high pressure electric gaseous discharge devices, such as metal vapor lamps for example, as the light source.

Luminaires with these light sources are quite expensive as compared to incandescent light sources for example because they require a certain amount of auxiliary equipment for their operation. Further expense is incurred, requiring the purchase of a new luminaire, each time a customer wants to obtain a different light distribution pattern.

In view of the foregoing, the principal object of this invention is to increase the versatility of a luminaire for lamps of the metal vapor type without a significant increase in cost.

This and other objects, advantages and features are attained, in accordance with the principles of this invention by providing a simple means of shifting the relative location of the reflector with respect to the light source in a plane parallel to the longitudinal axis of the light source whereby a different light distribution pattern is obtained.

In the accompanying drawing, FIG. 1 is a front elevational view partly in section of a luminaire embodying the principles of this invention.

FIG. 2 is a fragmentary detail on an enlarged scale of the luminaire of FIG. 1, showing particularly the means employed for varying the relative location of the reflector with respect to the light source.

Referring now to the drawings, the luminaire illustrated therein comprises a housing 2 for the auxiliary electrical equipment normally associated with high pressure electric gaseous discharge devices of the metal vapor type, a lamp socket 4 secured to and depending from the bottom of the housing 2, a lamp 6 seated in the socket 4 and a reflector 8 within which the lamp 6 is disposed. The reflector 8 seats in a reflector support ring 10 with a gasket 12 disposed therebetween. The ring 10 is secured to a spider 14 which is attached to and depends from the bottom of the housing 2 and is concentric with the lamp socket 4. The reflector 8 is secured to the spider 14 by latches 16.

As shown in FIG. 1, the top of the spider 14 is secured directly to and fits snugly against the bottom of the housing 2. When so located, the light source or lamp occupies a certain relative location with respect to the g reflector 8 and thus a certain light distribution pattern is obtained. On the other hand, if a different light distribution pattern is desired, an adapter ring 18 is located between the spider 14 and the housing 2 as shown in phantom in FIG. 2. By interposing the adapter ring 18 be10 tween the housing 2 and the spider 14, the reflector 8 is displaced downwardly a distance substantially equal to the width of the ring because the reflector 8 is attached to the spider 14 by latches 16. The extent of this displacement is illustrated by the showing in phantom in 15 FIG. 1 of the new locus of the peripheral lower edge of the reflector 8. Since the position of the lamp socket 4 has not changed, this displacement of the reflector 8 effects a change in the relative location of the reflector with respect to the light source and thus provides a dif20 ferent light distribution pattern. It will be readily apparent to those skilled in the art that other adapter rings of different lengths may be employed to obtain other light distribution patterns without departing from the spirit of this invention.