US 1950380 A
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March 13, 1934. G. ARRAS LIGHTING FIXTURE Filed July 9, 1932 Patented Mar. 13, 1934 UNITED STATES PATENT OFFlCE Claims.
This invention relates in general to lighting fixtures and has more particular reference to a. reflector in which the contour is varied to build up lighting intensity to secure unusual uniformity 5 in the lighting of rectangular areas.
The principle object of the invention is in the provision of a reflector which deflects light rays from a central source of light to build up the lighting intensity in the four corners of a room 13 or in the corresponding areas as referred to the source of light.
A further object of the invention is to provide an improved reflector in which a portion of the li ht is diverted through openings in the reflector 1 to illuminate the space back of the reflector and the lamp holder projection of the reflector itself.
A still further object of the invention is in the provision or" a lighting reflector made of a single piece of material having openings disposed to prevent direct rays of the lamp from passing therethrough and located to assist in the deformation of the reflector dome and skirt for producing the desired lighting effect.
Other objects of the invention will appear hereinafter, the preferred construction being illustrated in the accompanying drawing.
In the drawing, Fig. 1 is a side elevation with parts broken away, of an electric fixture embodying this invention;
Fig. 2 is a plan view of the reflector showing the distribution of reflected light from the dome portion thereof;
Fig. 3 is a diagrammatic View showing the contour of the reflector and the distribution of reflecited light from one portion of the skirt thereof Fig. 4 is a diagrammatic view illustrating specular reflection of light toward the corners of a room or a rectangular area.
An'ordinary lighting fixture distributes illumination from a central lamp in a circle of which it is the center, but most lighting fixtures are used in rectangular rooms or they are disposed in parallel rows to light rectangular areas. The pres out invention relates to a reflector of particular formation for building up the light intensity at points which would be outside of the circle of light normally produced by the ordinary round reflectors now in use. In a large room where a numher of lights are installed at an equal distance about it at right angles to each other, this reflector will build up the light intensity at the intermediate points which would receive the poorest lighting with the present lighting reflectors, and obtains unusual uniformity of light'distribution over the entire area.
Referring now more particularly to the drawing, a lighting reflector as shown in Fig. 1, has a skirt portion 5 and a dome 6 joined to a lamp reflector may be made up of separate pieces sultrably joined together or it may be spun or pressed from sheet metal which is usually polished or coated with a reflecting material such as enamel in order to make it more effective and efficient in use.
Within the reflector is a socket 9 for holding a lamp: 10 of the filament type and having a filament 11 as the source of illumination.
To secure the desired results the skirt 5 of the reflector is generally round in contour but with four diverging points 12, each forming an angle of 135 degrees divergence and each side of the angle being tangent to and continuing in a curved portion 13 and providing a specular reflection portion 14 which is obtained from the inner glossy surface of the skirt whether it is of porcelain, enamel or polished metal and directing the specular reflection at right angles into the corners 15 of a room as represented in Fig. 4.
The dome 6 of the reflector has depressions 16 at four points just above the angular projections 12 of the skirt forming two triangular planes 17 which also direct light rays toward the theoretical corner of the room or bay in which the lamp is located. The direction of light from the reflecting surfaces of the dome between the triangular planes 17 and from the planes themselves are indicated by the dotted lines and arrows in Fig. 2, the small circles 18 representing the approximate point of reflection and the arrows the general direction of the light reflected from such surfaces.
Between the lower edges of the triangular planes 17 and the projecting points 12 of the skirt are diamond shaped openings 20 to permit.
the escape of some reflected light toward the ceiling. It is not actually necessary to provide these openings 20 at these points but the reflected light from the openings dispels gloom at the back of the reflector and partially illuminates the projection 7, and also facilitates the formation of the angular projection 12 of the skirt as well as providing the necessary material for forming the triangular reflecting planes 17. It will be noted furthermore that the lower edges of the planes 17 prevent the escape of any direct light from the filament 11 through the openings 20,
thus obviating any direct light rays at the sides' of the reflector and preventing the lamp or the filament from being seen through the openings. In Fig. 3 is a diagrammatic representation of the distribution of light from one only of the four sides of the reflector represented by the outline 22 between adjacent points 12 of the reflector. From this diagram it will be noted that the surfaces A and B combined embrace approximately one-half of a right angle (or 45 points 12 and that the circular section G exdegrees) the tangents forming an angle at the tends for approximately one-eighth of the circumference (or 45 degrees) so that the circular section C distributes and reflects all light which it receives back through the central axis as represented by the lines 23 and the rays do not diverge more than twenty-two and one-half degrees on either side from the desired line of reflection. The light reflected from the surfaces A and B is also distributed in the desired direction as indicated generally by the line 24 with a maximum divergence as represented also by the lines 23 of not more than twenty-two and one-half degrees.
Each of the other reflecting surfaces of the skirt between any two points 12 thereof causes a similar diversion and reflection of the light rays opposite thereto so that by locating the points 12 midway between the corners of a room or bay which it is desired to illuminate as represented in Fig. 4, a distribution of light is obtained in which the light intensity is built up at the corners thereby producing unusual uniformity of light distribution over the entire area and particularly in the corners of a rectangular area, either of a room or a rectangular area to which this reflector and lighting fixture is applied. Instead of the angular projections 12 of the reflector turning outwardly it will be seen that approximately the same effect is obtained if' the angular portions of the skirt are turned inwardly as represented by the broken lines 25 in Fig. 3, the angle between the sides of the projections being the same, approximately 135 degrees, the sides being parallel to the sides shown in full lines in Fig. 3, and although the reflection from the inwardly turned sides is directed to different rectangular corners, the total lighting effect from an entire reflector is the same as for the outward projections, as shown.
In a similar manner the triangular planes 1'7 may be depressed from the inside or project outwardly instead of inwardly as shown in Fig. 1, producing the same total lighting eifect for an entire reflector as if they are depressed inwardly as shown.
In all of the forms the result is that the light intensity is built up in the corners of a room, thereby tending to equalize the light distribution of a rectangular or square area.
1. An electric fixture comprising a reflector having rectangularly disposed corner portions and a central lamp, the reflector being shaped to project light from the lamp to build up light intensity between said corner portions for a uniform rectangular distribution at an angle to the rectangle of said corner portions.
2. In an electric fixture, a reflector approximately circular in shape but having obtuse angular projections at intervals in the sides for increasing thelight intensity from a central lamp at an angle between the adjacent projections.
3. In an electric fixture, an approximately round reflector having four equally spaced and obtuse angular projections for equally distributing light from a central lamp to a rectangular area, the angular projections being disposed between the corners where the light must be projected.
4. In an electric fixture, a reflector which is approximately round but has obtuse angular projections at four equi-distant points about the circumference, the projections being approximately of one hundred thirty-five degrees divergence.
5. A lamp reflector having obtuse angular pro- 'jections at four equi-distant points about the circumference of the reflector, the sides of the angles being tangent to and connected by an intermediate curved portion.
6. A lamp reflector having a connected dome and skirt, the skirt having obtuse angular projections joined by circular portions together making up an approximately circular reflector.
7. A lamp reflector having a connected dome and skirt, the skirt having angular portions extending outwardly from the dome and connected by curved portions and the dome having angular depressions adjacent the comers.
8. A lamp reflector comprising a connected skirt and dome, the skirt having obtuse angularly projecting corners extending outwardly from the dome and forming a light diverting opening between the dome and skirt at each of the corners thereof.
9. In a lamp reflector, a connected skirt and dome, the skirt having obtuse angular corners and the dome having angular depressions adjacent the corners and separated therefrom to form an angular opening between the dome and skirt at each of the corners for deflecting reflected light at the rear of the reflector.
10. An electric fixture comprising a central lamp and a reflector having angular corners, the reflector having a dome with angular depressions forming inclined triangular planes at each corner for projecting light from the lamp for a uniform rectangular distribution.
11. An electric fixture comprising a lamp and a reflector, the reflector having a connected skirt and dome, the skirt having angular projections, and the dome having angular depressions forming inclined light diverting planes, the projections and the planes together diverting light from the lamp to produce a uniform rectangular light distribution.
12. In a lamp reflector, a skirt portion inclined to the lamp having obtuse angular portions at four points of approximately one hundred thirty five degrees joined by circular arcs for substantially uniform rectangular distribution, the angular projections being disposed intermediate the corners of the distribution rectangle and the reflections from one side of the skirt between adj acent projections diverting light from the lamp to the diametrically opposite rectangular corner for building up the light intensity in that 10- cality.
13. A lamp reflector having an inclined reflecting skirt with obtuse angular corners, the sides of each angle subtending approximately one and a half right angles.
14. An electric fixture comprising a lamp and a reflector, the reflector having a connected skirt and dome, the dome having angular depressions forming inclined reflecting planes, the lower edges of the planes being separated from the skirt to provide alight diverting opening, and the lower edges being so disposed with respect to the edges of the skirt that direct light from the lamp filament will not shine through the opening.
15. A lamp reflector comprising a connected dome and skirt each having inclined angular corner portions connected by curved reflecting portions for modifying the distribution of reflected light from a central lamp whereby the specular reflection and the reflected light from the dome and skirt is built up in the angular portion between the angular corners of the reflector for producing a substantially uniform light distribution over a square area. GEORGE AREAS.