US2523394A

US2523394A - Direct lighting luminaire

Info

Publication number: US2523394A
Application number: US546512A
Authority: US
Inventors: Thomas W Rolph; Franck Kurt
Original assignee: Holophane Corp
Current assignee: Holophane Corp
Priority date: 1944-07-25
Filing date: 1944-07-25
Publication date: 1950-09-26
Anticipated expiration: 1967-09-26

Description

Sept. 26, 1950 w, ROLPH ET AL 2,523,394

DIRECT LIGHTING LUMINAIRE Filed July 25, 1944 2 Sheets-Sheet l I 24 /f M :7 l J. C]. v4:.- /0

INVENTOR. THOM/IJ W- ROLPH .KUPT FRANCK A TTORNEY Sept. 26, 1950 T. w. ROLPH ET AL 2,523,394

DIRECT LIGHTING YLUMINAIRE Filed July 25, 1944 2 Sheets-Sheet 2 INVENTOR. THOMAS W. ROtPH q KURT FRANCK ATTORNEY Patented Sept. 26, 1950 DIRECT LIGHTING LUMINAIBE Thomas W. Rolph and Kurt Franck, Newark, Ohio, assignors to Holophane Company, Inc., New York, N. Y., a corporation of Delaware Application July 25, 1944, Serial No. 546,512

Claims. 1

The present invention relates to direct lighting luminaires, and is more particularly directed toward direct lighting luminaires employing high intensity tubular light sources such as high in tensity mercury lamps.

The 3000 watt 120,000 lumen mercury lamp, which is about 5 long and slightly more than an inch in diameter, is an extremely high intensity light source and gives off a great amount of heat and owing to the heat developed by the lamp it requires very open mounting to facilitate cooling. It is well adapted for high bay lighting.

The present invention contemplates luminaires more particularly designed to employ light sources of the type referred to wherein the fixture is designed for precise light control and re-direction and provided with adequate ventilation to maintain all parts at satisfactory operating temperatures.

According to the present invention the light control i effected by reflectors disposed to form a horizontal inverted trough whose side walls intercept light in a wide region above and below the horizontal and direct this light generally downward, part of it crossing the axis and part of it not crossing the axis, so that the light from one side of the reflector is mixed with light from the other side. The reflectors forming the trough are separated or spaced apart above the lamp to facilitate the passage of heated air. Supplemental reflectors intercept the upwardly emitted light and reflect it into useful directions.

The accompanying drawings show, for purposes of illustrating the present invention, two embodiments in which the invention may take form, it being understood that the drawings are illustrative of the invention rather than limiting the same.

In these drawings: 7

Figure l is a perspective view of a pendent luminaire;

Figure 2 is an end elevational view with parts in section;

Figure 3 is a fragmentary cross sectional view;

Figure 4 is a longitudinal sectional view; and

Figures 5 and 6 are views similar to Figures 2 and 4 showing a modified form of construction.

The fixture shown in Figures 1 to 4 employs two end members l0, [0 usually in the form of casings. They have two downwardly and outwardly divergent ribs or branches H, II. The end members are secured together by four sheet metal tie members I2, 12 at the top and I3, l3 at the bottom, suitable bolts I 4 being employed to hold the parts together, and have upwardly extending apertured lugs l5 by which the fixture may be suspended. The lower tie members I3 are upwardly opening channels, while the upper The tie members on each side'of the fixture support arch shaped glass plates ll, [1. These plates are preferably made of prismatic glass pressed in the form of flat sheets, then heated and bent to the proper profile and subjected to heat treatment. The outer surface of these plates is smooth, while the inner surface is made up of prismatic ribs l8 shown at a larger scale in Figure 3. The angle between the faces of these ribs is indicated at being 90 and the ribs are symmetrical. The reflector plates typically have such a contour that the incident faces of the mitered ribs are at right angles to light emitted from a source L. The light rays are not therefore deviated when they enter the glass. They strike the outer surface at angles suitable for total reflection and pass out of the glass through the other surface of the same or a still different rib without deviation, so that the angle between the incident rays, such as l9, and the reflected rays, such as 20 Figure 3, is a right angle.

In order to maintain a screening angle of 30 below the horizontal, or from the nadir, the luminaire is designed so that the lower edge of the reflector is approximately 60 from the nadir as indicated. The horizontal light rays, such as 2 I, striking the reflector with mitered ribs will be diverted directly down as indicated at 22. Typical light rays above the ray 2i are indicated by the ray 23, this being near by the uppermost ray and approximately 30 above the horizontal. It is reflected out as indicated at 24, so as to pass just below the lower edge of the reflector. Upwardly directed light will therefore be directed downwardly by the reflector and spread away from the nadir to regions approximately 30 from the nadir without crossing the axis. A typical ray below the horizontal is indicated at 25, and this ray is reflected out as indicated at 20. The direct light below the horizontal will therefore be reflected downwardly and across the luminaire axis with the widest spread of the reflected light approximately 30 from the nadir so that this light reaches the same regions as the upwardly directed direct light intercepted by the upper part of the reflector on the other side of the luminaire. The fixture is therefore well adapted to provide a light pattern wherein there is a very definite cut off at about 30 below the horizontal'and there is a high building up of light below the luminaire tie members 42 have outwardly extending flanges in a region about 40 wide with a sharp falling off in intensity up to the region about 60 from the nadir. The 90 miter ribs are preferred as they are more efficient than ribs with other angles. With them the profile of the reflector is also better than with other angles. I

In as much as the

reflected rays

22, 24, 26, have a constant deviation from the corresponding incident rays 2|, 23 and 25 (90 in the example shown) the profile of each side of the reflector coincides with a curve which makes the proper uniform angle (45 in the example shown) with the radiants. These radiants are coincident with the light rays in transverse planes. The extreme radiants make equal angles above and below the median radiant, which is horizontal. The length of the arc of the curve and its position. are so selected that'light reflected'from the top of the reflector escapes below the bottom edge of the reflector on the same side while none of the light reflected from the lower part of the reflector is at angles farther from the nadir than the most widely, spread light reflected from. the top of the reflector.

The glass plates rest in place in the luminaire frame and are merely held against falling out by clips 30, and they are able to expand and contract so as to withstand the extremely high "temperature to which they are subjected.

As shown in Figures 2 and 4 the fixture is provided with supplemental upper reflector 34 adapted to return the upwardly direct light not intercepted by the main reflector in a generally downward direction. This upper reflector is spaced substantially from the upper tie members l2, 12 so as to provide ventilation passages as They are held together by

tie members

42 and 43. The upper tie members support angles 44. The angles 44 and lower tie members 43 support reflectors II, the same as those previously described, and these are held against accidental removal by clips 45.

In Figures 5 and 6 the upper reflector 46 is a prismatic glass reflector with outer totally reflecting prisms 41 so that the upwardly directed rays 48 are returned toward the light source. The fixture of Figures 5 and 6 has hanger eyes indicated at 49.

The two supply wires and 5! (Figure 4) for the fixture are brought into a splicing chamber 52 in one end member and one wire fastened to the terminal of a, socket holder 53 while the other wir is spliced to a wire 54 which comes out through hole 55. The wire 54 passes down along the end member through bushings 56 carried by the end members, up along the other end member and into the other splicing chamber where it connects to the other lamp socket. In this manner the wiring is removed as much as possible from the heat of the lamp.

Since it is obvious that the invention may be embodied in other forms and constructions within the scope of the claims, we wish it to be understood that the particular forms shown are but a few of these forms, and various modifications and changes being possible, we do not otherwise limit ourselves in any way with respect thereto.

What is claimed is:

1. A direct lighting luminaire comprising a horizontal tubular lamp, end members spaced beyond the ends of the lamp and having legs which downwardly and outwardly diverge from the region of the lamp axis, ti members connecting the ends of the legs and having upwardly opening channels, other tie members above and close to the source but spaced for ventilation, reflecting panels whose lower edges are received in the channels of the lower tie members and whose upper edges are secured against the upper tie members, and a downwardly acting reflector above and between the upper tie membersand whose edges are spaced from the upper tie members to provide ventilation passages.

2. In a luminaire, a light source emitting divergent rays, a prismatic reflector intercepting divergentrays in a zone of substantially less than and transmitting them without change of divergence, the reflector being generally concave to incident rays and having an externally smooth outer surface and an inner surface, the latter being composed of ribs each with an incident face substantially normal to the rays incident thereon and a second light emitting face at substantially right angles to the incident face, the bisectors of the rib faces being substantially normal to the outer surface, whereby light rays in the reflector strike said outer surface at angles for total reflection through the second faces of the ribs and for emission at substantially 90 to the original direction.

3. A luminaire as claimed in claim 2, wherein the angle of the zone of light intercepted by the reflector is substantially 60.

4. A luminaire comprising a horizontal rectilinear light source and an inverted specular reflecting trough symmetrical bout a, vertical plane through the source and having on each-side of said vertical plane a profile generated by the movement parallel to the axis of the light source of a generatrix in the form of an arc of a curve which makes uniform angles with radiants emanating from the axis of the source, the portions of the reflector above the median radiant being disposed in space to reflect direct light toward the nadir without crossing said vertical plane and with an angular spread therefrom equal to the angle between the median radiant and the uppermost radiant, the portions of the reflector below the median radiant through the source being disposed in space to reflect light toward nadir and across said vertical plane with the same angular spread therefrom.

5. A luminaire as claimed in claim 4, wherein the median radiant is in a horizontal plane.

6. A luminaire as claimed in claim 4, wherein the reflector is prismatic, externally smooth and provided with internal ribs with incident faces normal to direct light and emergent faces normal to reflected light.

7. A luminaire as claimed in claim 4, wherein the reflector is prismatic, externally smooth and provided with internal ribs with incident faces normal to direct light and emergent faces normal to reflected light, and the median radiant is in a horizontal plane.

8. In a luminaire, the combination with a horizontal rectilinear light source of an inverted specular reflecting trough extending substantially 30 below the horizontal plane through the source and 30 above said plane, and having in vertical planes a profile generated by the movement in a direction parallel to the light source of generatrices in the form of sectorsof curves which make an angle of substantially 45 with the radiants thereof, the radiants emanating from the axis of the light source.

9. In a luminaire, the combination with a horizontal rectilinear light source of an inverted prismatic reflecting trough extending substantially 30 below the horizontal plane through the source and 30 above said plane, and having in vertical planes a profile generated by the movement in a direction parallel to the light source of generatrices in the form of sectors of curves which make an angle of substantially 45 with the radiants thereof, the radiants emanating from the axis of the light source, the reflector being externally smooth and having internal ribs with incident faces normal to incident light and emergent faces normal to the incident faces.

10. In a luminaire, the combination with a horizontal rectilinear light source of two transparent rectilinear reflectors each occupying a zone substantially 30 above and 30 below the horizontal plane through the source, each having a smooth lower surface consisting of miter ribs and an externally convex, totally reflecting surface with a slope of substantially 45 at the level of the light source, a decreasing slope above the said level and an increasing slope below said level whereby upwardly emitted direct light in the zone above the horizontal is reflected downwardly and away from the vertical median plane through the luminaire and downwardly emitted direct light in the zone 30 below the horizontal is reflected downwardly and toward the median plane.

THOMAS W. ROLPH.

KURT FRANCK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date A 2,015,235 Rolph Sept. 24, 1935 2,314,103 Raizner Mar. 16, 1943 2,337,437 Allen Dec. 21, 1943 FOREIGN PATENTS Number Country Date 627,376 France of 1927 652,708 France of 1928 36,540 France of 1930 467,411 England of 1937 699,506 Germany of 1940 832,638 France of 1938