US2316546A - Lighting apparatus - Google Patents

Description

April 13, 1943. v G, ANDERSON El'AL LIGHTING APPARATUS Filed May 31, 1940 2 SheetsrSheet 1 fllllifllllu ATTORNEY April 13, 19 3- v. G. ANbERsoN'a-r'AL 2,31 ,5 6

LIGHTING APPARATUS Filed May 31, 1940 2 Sheets-Sheet 2 CL 5 F 7.

CANDLE Pow'ae INVENTORS VICTOR G'E/ST ANDERSON HAROLDY WILLIAM BAMBI/SCH ATTORNEY Patented Apr. 13, 1943 2,316,546 LIGHTING APPARATUS Victor Geist Anderson, New Rochelle, and Harold William Rambusch, Brooklyn, N. Y., assignors to Rambusch Decorating Company, New York, N. Y., a corporation of New York Application May 31, 1940; Serial No. 338,164

13 Claims.

The present invention relates to lighting apparatus, and is more particularly directed toward lighting apparatus adapted to use long light sources and rectilinear specularreflectors and to provide on a parallel secondary reflecting areasuch as a ceiling or wall, or on a parallel working area-such as a deska wide spread of light in directions at right angles to the axis of the source, the projected light having a sharp cut off line adjacent the normal from the mouth of the reflector to the surface to be illuminated and spreading outwardly from said cut ofi line over a long area whose Width is substantially the length of the light source.

The lighting apparatus is especially designed for recessed mounting in a wall or ceiling adjacent the corner formed by an intersecting wall or ceiling and for projecting beams of specularly reflected light of controlled spread and direction toward said intersecting wall or ceiling.

According to the present invention the long light source is generally disposed parallel with the corner formed by the intersecting planes, back of one plane and having a long narrow window opening, and specular reflectors are provided which form a trough whereby the light is reflected out of the window opening toward the other plane to be illuminated. The reflector forming the side trough farthest from the corner is employed to distribute specularly reflected light on said plane outwardly from the corner through a substantial angle from the normal plane, which may be in the neighborhood of 60, and cover a width equal to twice the spacing of the lighting apparatus from the corner. The side of the trough nearer the corner is employed to distribute light over the more remote parts of the plane to be illuminated. The lighting apparatus may conveniently be made up in units adapted to carry one or more long light sources end to end and may be mounted in a wall in the neighborhood of two or three feet below the ceiling so that controlled beams of reflected light are spread over very large ceiling areas extending out from the corner.

The present invention also contemplates that when the lighting apparatus is recessed in the wall for ceiling illumination the light source and reflectors will be so arranged that no direct or controlled reflected light is emitted below the horizontal, whereby sharp shadows may be avoided on adjacent walls as Well as glare.

The invention also contemplates the use of a light baflle so arranged that scattered light from the upper reflector will be intercepted and the upper reflector screened against observation. This baffle may receive direct light from the source and scattered light from the lower reflector whereby it will' be illuminated and form a decorative feature.

Other and further objects of the invention will appear as the description proceeds.

The accompanying drawings show, for purposes of illustrating the present invention, two of the many 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:

Figures 1 and 2 are top plan and front elevational views of a piece of lighting apparatus designed for recessed mounting in the wall and using two long light sources in line;

Figure 3 is a front elevational view of the same at an enlarged scale with parts broken away and parts in section; V

Figure 4 is a vertical sectional view on the line 4-4 of Figure 3;

Figures 5 and 6 are fragmentary sectional views on the lines 55 and 6-6, respectively, of Figure 4; I

Figure '7 is a diagrammatic view illustrating the spread of the light rays over the ceiling;

Figure 8 is a view similar to Figure 7 showing a photometric curve taken in the vertical plane through the center of the lighting unit; and

Figure 9 is a sectional view through a modified form of construction.

1 In the form shown in the drawings the lighting apparatus employs a long narrow housing [0 having a front wall II, bottom wall I2, rear wall [3, end walls l4 and iii, a central partition l6 and a top wall [1, the front portion is of which slopes upwardly so that the rear wall It of the housing may be narrower than the front wall II. The front wall H has two long narrow window openings IS with the lower edges 20, 20 spaced a substantial distance above the bottom of the housing and the upper edges 2 I, 2| located close to the top of the housing. Duplicate lighting equipment is placed behind each window opening.

Near the lower rear corner of the housing, as shown in Figure 4, is a longflat bar or strap 22 which is fixedly. held 'in place by a number of brackets 23. This bar is tapped at spaced intervals to receive screws indicated at 24 and 25. The screws 24 are employed to secure the portion 26 of a rectilinear reflector member 2'! in place. The front edge of the reflector 21 is secured to brackets 28 carried by the inside of the front wall I I and the mid-portion is secured to brackets 29 carried by the end wall It or it and the partition H5.

The length of the reflector 27 is such that it extends from the partition to one of the end walls. It is notched at the ends, as will be apparent in Figure 5, to receive fluorescent lamp sockets to and the sockets are secured in place by screws 3i threaded into the mounting bracket 32. These sockets are adapted to receive and support a fluorescent lamp indicated at 33. Other forms of long light source may be used, if desired.

The screws are employed to securethe lower more remote from the corner formed by the intersection of the ceiling plane and the normal or wall plane than the upper side of the trough. The lower side of the trough, as is apparent from the drawings, may be designed to intercept somewhat more than one-quarter of the output of the lamp and will reflect it through the virtual light source F spreading it in a comparatively wide beam, as indicated by the angle A of Figures 4 and '7. This angle is in the neighborhood of 60. Owing to the exaggerated thicknesses of material I necessary in making Figure 4, the more vertical portion 34 of an upper rectilinear reflecting 'element 35 to the bar or strap 22. element is cut back, as will be clear from Figure 5, so as to clear the screws 3i. with large holes 35 to accommodate the heads of. the screws 24. The reflecting element 35 has a flange 3i and issecured to an angle member 33 by screws indicated at 39. An intermediate portion of the upper reflector member 35 is secured to the end walls and partition by screws 40 threaded into brackets The reflecting elements 27 and 35 are preferably made of highly specular metal and they form a trough which reflects most of the light' output of the source through the window opening. The lower side 2'! of the trough is rectilinear and of elliptical contour with one focus F at the axis of the light source and the conjugate focus F substantially in the plane of the window opening and spaced some distance above the lower edge 29 of the window opening so that the major axis FF makes an acute angle a with the front wall I I. The upperside of the trough 35, below line 35a (level with edge 26 of the window), has a portion 35b of elliptical contour with the same foci F and F. The upper portion 350 of the reflecting element 35 is of elliptical contour with one focus F at the axis of the light source and its conjugate focus F" spaced a short distance below the upper edge 21 of the window opening and substantially in the plane of the window opening. It is sufliciently above the level of the upper edge of reflector 350 to insure the reflection of all direct rays from the source above the horizontal. The major axis FF of this ellipse is at a more acute angle b with the front wall of the housing.

Baffle plates M are carried in. the housing. They are supported on angle brackets 42 carried by the end walls it and i5 and the partition I6 and are held in place by upwardly bent ears 43 on these brackets and by screws 44 which fasten them to straps welded or otherwise secured inside the front wall H. The rear edge 4! of the bafile is just in front of the line connecting the axis F of the source 33 and the top of reflector 350.

The space between the baflle and the lower edge of the window opening is of sufiicient width to permit one to reach in for lamp installation and renewal. The upper reflector 35 may be released by removing the supporting screws and the baffle may be released by removing the screws 44, and these parts may then be moved up into the upper part of the housing as indicated by the dot-anddash lines, so as to give access to the-lamp auxiliary as.

\Vhen the lighting apparatus is installed in a wall W, as indicated in Figure '7, spaced a distance below the ceiling CL, the ceiling may be lighted by the light projected from the lighting apparatus. The lower side 21 of the trough is This reflecting I It is provided ray 5i} appears to be farther from zenith than it would be in actual construction. In practice it will send light practically to the corner. It will thus be seen that somewhat more than one- '7 quarter of the output of the source, less reflection losses,.may be distributed over a ceiling width which is approximately twice the distance from the ceiling down to the lighting apparatus. The intensity of the beam increases as the reflected light rays approach the major axis FF oi the ellipse.

The portion 35b of the upper side of the trough subtends an angle of about 45 about the axis of the source and reflects the light in this zone through a virtual light source at the focus F in a condensed beam B directed on the other side of the major axis. This light, as will be apparent from Figure '7, is spread over a very remote area of the ceiling. This area is, however, comparable with the area lighted by the beam A which is near zenith.

The upper or third reflector 35c subtends an angle of about 45 about the axis of the light source and-it reflects this light through a condensed beam C emanating from the upper conjugate focus F". This light is below the major axis FF" and is spread over a wider area of the ceiling. The reflector 350 is designed so that the higher angled light in the beam C lights the same area of ceiling as the lower angled light in the beam A.

There is a small amount of direct light from the source which passes through the lower part of thexwindow in the same general direction'as the light in the beams B and C so that this direct light builds up the illumination of the more remote parts of the ceiling.

The light baflle '4l intercepts higher angled light from'the source and scatters it downwardly. It avoids the building up of a bright spot on the ceiling by high angled direct light and also avoids observation ofthe upper part of the reflector 350 when the apparatus is viewed from usual angles. The lower edge'ZlI of the window opening is preferably'place'd in such a positionas to prevent any direct or reflected light from the source passing below the bafile 4| from being directed below the. horizontal. This is indicated by the rayr5l which originates at the-top of the light source 33. Some scattered light passing upwardly behind the 'bafile falls on the inner surface of the sloping part ['8 of the top of the housing. This surface is preferably diffusing and may be painted a desirable color so that the scattered light will illuminate it and bring out the decorative feature of the aperture. A similar harmonious color may be placed on the bottom of the battle 4|. Either or both of these surfaces may be painted black, if desired.

The aperture formed by the window opening is larger than the spacing of the foci F and F paratively large light source. The light which goesdownwardly and rearwardly from the light source and falls on'the lower back part 34 of the upper reflector element isscattered and some escapes so as to be reflected in random directions.

When the lighting apparatus is recessed'behind one of the planes forming a right dihedral angle, as indicated in Figures 7 and 8, the output of the unit is spread over a very large area of the other plane forming the dihedral angle such, for example, as the ceiling CL indicated. The dominant output from each unit will have a width equal to the length of the source and will cover a substantial distance from the corner, as will be apparent from the photometric curve of Figure 8 and the ceiling illumination curve 52 of Figure 7. Where a number of units are placed together end to end the laterally spreading rays from the units will overlap. The observer will not look into the units, but will see two long narrow decorative openings.

Figure 9 shows two units optically similar to the units shown in the preceding figures, but placed back to back so that when such units are hung below the ceiling each unit sends a wide spread of light on to the ceiling with comparatively sharp cut off line above the edge of the unit. A central lamp 53 may be provided for lighting the region directly over the unit and for giving a lower intensity illumination when desired.

When the units are inverted the light is emitted at controlled angles below the horizontal, and when they are mounted below eye level the units are suitable for the lighting of desks, display tables, floors, floor coverings and other generally horizontal surfaces normally viewed from above.

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

What is claimed is:

1. Means for projecting light onto one of the surfaces forming a right dihedral angle throughout an area of substantial length and width extending to the corner thereof, comprising a lighting appliance recessed behind the plane of the other surface of said dihedral angle and having a window in the plane of said other surface, a light source parallel with the corner, and a light reflecting trough made of highly specular material disposed about the source and extending toward the edges of the window, the reflecting surfaces being of substantially elliptical contour with common foci at the light source, the conjugate foci being in the plane of the window, being spaced and adjacent the edges of the window, the wall of the trough remote from the corner spreading the specularly reflected light throughout a predetermined angle from the plane of the second surface of the dihedral angle so as to illuminate a predetermined region extending outwardly from said corner, the wall of the trough nearer the corner having a portion substantially elliptical with respect to one conjugate focus and' another portion substantially elliptical with respect to the other conjugate focus more remote from the corner said portions projecting specularly reflected rays into angles generally beyond those of the rays reflected by the'remote side of the trough for illuminating areas of the first surface more remote from the corner.

2. Illuminating apparatus comprising a body having a face provided with a long narrow window opening with parallel edges, a rectilinear light source parallel with the face of the body and the edges of the opening, a relatively wide rectilinear reflector of substantially the same length as the source and having an edge adjacent one edge of the window opening and extending to a line adjacent the light source, said reflector being of elliptical contour with one focus at the axis of the light source and the conjugate focus substantially in the plane of the window opening and near the said edge thereof and having its major axis at an acute angle with said face on the side toward said reflector, a second narrower rectilinear reflector of elliptical contour and the same foci and disposed on the opposite side of said major axis, the said two reflectors intercepting nearly all the light emitted to one side of said major axis and a substantial amount of that emitted on the other side of the major axis and redistributing this light from a virtual source at said conjugate focus in a beam, diverging on both sides of the said major axis, of maximum intensity near said major axis and of diminishing intensity as said face is approached, and a third rectilinear reflector extending from the edge of the second reflector a substantial distance toward the other edge of the Window opening and of elliptical contour with one focus at the axis of the light source and the conjugate focus adjacent said other edge of the window opening and substantially in its plane, the third reflector intercepting light which misses the second reflector and reflecting it through said window opening and into the same general direction as the second reflector.

3. Apparatus such as claimed in claim 2, having a rectilinear 'baille extending diagonally inward from the mid-portion of the window opening between the conjugate foci and disposed between the beams of reflected light from the second and third reflectors to screen the second and third reflectors when viewed from a position substantially outside the projected beam.

4. Apparatus such as claimed in claim 2, wherein the outer edge of the second reflector is located insubstantially a plane normal to the plane of the window opening through the first mentioned edge of said opening, whereby the source and second reflector are screened against observation at angles up to the normal to the face of the body.

5. Apparatus such as claimed in claim 2, wherein the light source is of substantial diameter and the outer edge of the third reflector is located so that the critical rays falling thereon from the portions of the source nearer the conjugate foci are reflectedwithout crossing the plane from said edge normal to the window opening.

6. Apparatus such as claimed in claim 2, and having a bafile extending diagonally inward from the mid-portion of the window opening between the conjugate foci and disposed between the beams of reflected light from the second and third reflectors to screen the second and third reflectors when viewed from a position substantially outside the projected beam, the inner edge of the baffle being substantially in line with the extreme rays from the source falling on the third reflector.

7. A luminair adapted for recessed mounting in a building wall adjacent the ceiling'and comprising a long narrow housing having a front wall, end, bottom, top and rear walls, the front wall having along narrow window opening below the ceiling, a longitudinally extending bar secured inside the housing near the lower rear corner thereof, forwardly extending lamp sockets secured to the ends of the bar, a lamp extending between the socket and arallel with the'front wall of the housing, a lower rectilinear specular reflector secured to the bar and the front of the housing and having an elliptical contour with one focus at the axis of the lamp, and the other above the lower edge of the window opening and in the plane of the window opening, and an upper rectilinear reflector secured to the bar and to the upper part of the housing, the upper reflector having a narrow lower portion of elliptical contour with the same foci as the lower'reflector and a wide upper portion of elliptical contour with one focus at the axis of the lamp and its conjugate focus in the region of the upper part of the window opening.

8. A luminair such as claimed in claim "I, having lamp auxiliaries secured in the upper rear part of the housing and wherein the upper refiector is movable upwardly and forwardly within the housing to afford access to the lamp auxiliaries.

9. A luminair such as claimed in claim 7, having a light baiile extending from one end wall to the other and rearwardly from the front wall to be between the beams reflected by the two portions of the upper reflector.

10. A luminair such as claimed in claim 7, having a light bafiie extendin from one end wall to the other and rearwardly from the front wallto be between the beams reflected by the two portions of the upper reflector, and lamp auxiliaries secured in the upper rear part of the housing, and wherein the upper reflector is movable forwardly and upwardly and the baflle is movable upwardly within the housing to afford access to the lamp auxiliaries.

11. A luminair comprising a rectilinear light source and a light reflecting trough made of highly specular material, the portion of the trough to one side of the source being of elliptical contour with one focus at the axis of the light. source and the conjugate focus adjacent to Jout spaced from th corresponding edge of the trough and of a'length to "bringsaid edge nearly to the perpendicular to the major axis passing through the conjugate focus so that the light reflected thereby after passing through the conjugate focus occupies an angle substantially lessthan 90 to one side of the major axis, the opposite side of the trough having a narrow portion adjacent the source of elliptical contour with the same foci so that the reflected light from the narrow portion of the trough after passing through the conjugate focus occupies a narrow angle on the other side of the major axis from that reflected from the first portion, and a wider portion also forming part of an'ellipse with its'major axis divergent from the major axis of the first ellipse with one focus at the axis of the source and the conjugatefocus parallel to the first conjugate focus, at a greater distance from the source than the first conjugate focus, spaced further from the said outer edge of the trough than said first-mentioned conjugate focus and substantially in the plane of the rays reflected from the said outer edge of the firstmentioned side of the trough so that reflected light from said wider portion after passing through the second conjugate focus occupies a region below the major axis of the second ellipse and is projected in the same general direction as the light reflected by the narrow portion.

12. A luminair such as claimed in claim 11, having a baille plate between the specularly reflected rays from adjacent edges of the wide and narrow portions of the reflecting trough, the inner edge of the bafile plate being just outside the line between the axis of the light source and the outer edge of the said wider portion.

'13; A luminair such as claimed in claim 11, having a light diffusing member extending from the outer edge of the said wider portion of the trough to the plane of the conjugate foci to receive scattered light from the source and form in conjunction with the outer edge of the firstmentioned portion of the trough a long narrow window opening.

VICTOR GE IST ANDERSON. HAROLD WILLIAM RAMBUSCH.

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