US2033235A - Direct lighting unit - Google Patents

Description

March 10, 1936.

c. E. FERRI-:E vE-r AL i' 2,033,235

DIRECT LIGHTING UNIT.

Filed June 2a, 1935 2 sheets-Shura Patented Mar. l0, 1936 PATENT oFFlcE DIRECT LIGHTING UNIT Clarence Errol Ferree and Gertrude Rand Ferree, Baltimore, Md.

Application June 29, 1933, Serial No. 678,177

3 Claims.

In the designing of desk lamps, table lamps, floor lamps and the like, an important difficulty encountered is due to the fact that the lighting unit must be adapted for use in the frontal hemi- 5 sphere, i. e.. in front of the reader or worker. With most desk lamps there is a high degree of glare on the work which is very uncomfortable and irritating. Very often the effect resulting from the glare of the opening is similar to that of a spot light, and in order to shield the eye from this glare, the tendency is to lower the opening below the level of the eye. In proportion as this is done the circle of illumination is narrowed so that the rays are concentrated on the work l5 and the glare is thus increased, the effect being more and more that of a spot light, This limited spread of illumination is further undesirable because it does not illuminate the entire working field and because the glare of the highly illumi- 20 nated area is greatly increased by the sharp contrast with its darker surroundings. This is particularly noticeable when there is no other illumination present. The fundamental difficulty is that in order to shield the eye from the glare 25 from the source of light, this source is placed too near to the work, the glare being in effect subtracted from the unit at the expense of adding it to the work.

'I'he invention relates to an improved type of desk, floor or table lamp also adapted for use as a bed lamp. This improved lighting unit is absolutely glareless with bulbs of either low or high wattage. It can be placed at a sufficient height 35 above the work to give a wide eld of illumination,

its construction being such that the spread of light increases at a high ratio in proportion to the distance of the surface to be illuminated from the source of light. The light from the im- 40 proved unit is also well diffused and uniformly distributed, the glare on the work being reduced to a minimum. Also, high intensities of light may be obtained and daylight color and composition may be had. It is also possible to preserve 45 the natural whiteness of the light when a Mazda or similar bulb is used, by the omission of all reflecting surfaces within the housing. This makes it possible to obtain a white light without the use of correcting fllters.

50 The lighting unit of the invention is dependent for its operation on the principle of direct illumination but is so devised that the eyes are completely protected from contact with the direct rays. In this way the worker is given vthe full 56 benefit of the illuminating effect of the direct rays on the work, but is, on the other hand, completely protected from the glare.

In the preferred form of the invention the direct rays thus utilized are modified by means of a diffusing member through which all the light discharged from the unit is passed and as the illumination from the unit is all directed downwardly or at a downward incline, the entire output of rays from the source of light is utilized by means of a reflector or reflecting surfaces on the 10 inside of the casing or housing.

'Ihe highly beneficial result thus generally outlined is obtained by means of ballles which are preferably combined with a diffusing plate or plates as aforesaid, all of which baflles are disposed downwardly in the general direction of the work. These baiiies are of a width so proportioned to the spacing that the direct rays preferably diffused are not only directed downwardly toward the work but are so downwardly inclined as to pass below the level of the eyes of the worker observing the work in and from any normal attitude and location which the worker may assume. The unit is therefore particularly adapted for use as a desk lamp, a table or floor lamp or a bed lamp and due to the wide spread of the illumination and complete protection of the eyes, it is also well adapted for use as a bridge lamp, and possesses unusual advantages as a general reading lamp.

In the accompanying drawings we have illustrated a lighting unit embodying the features of our invention in the preferred form.

In the drawings:

Figure l is an elevation of a unit adapted for use as a table, desk or floor lamp and having ver` tical baffles at the center and inclined baflles on four sides. The construction shown is partially broken away to include a vertical central section.

Figure 2 is a fragmentary sectional top plan 40 taken on the line 2, 2 of Figure 1.

Figure 3 is a bottom plan drawn to a reduced scale.

Figure 4 is an elevation of the unit made round instead of square and mounted on a stand which is broken away intermediately to indicate indefinite height, the illustration being applicable to either a desk or floor lamp.

Figure 5 is an elevation corresponding to Figure 1 showing a modified form of unit having the 50 baffles on one side only, the fourth side which is disposed toward the reader, having the baffles. This form is particularly adapted for use as a bed 1amp, the bottom baffles are inclined in the direction of the side baliles. I M

Figure 6' is a bottom plan view of the unit, Figure 5.

Figure '7 is a. perspective view of the same tipped to the normal position in which it would be utilized in reading.

' Figure 8 is an elevation of a wall type of unit having vertical batlles at the bottom or center` and inclined bailles on three sides, and the casing on the fourth side being closed so that it may be placed in close contact with the wall and conveniently attached thereto and otherwise utilized at one side of a desk or table set against the wall to throw the light on a downward inoline in three directions.

Referring to the drawings by numerals, .each of which is used to indicate the same or similar parts in the different figures, the construction shown in Figures 1 to 4 consists of a rectangular or round casing or housing I, having a top portion 2 which may, if desired, be inclined downwardly from the center, the inner surface at 3 being used as a reflector or a suitable separate reflector may be provided within the casing as hereinafter described or the reflecting surfaces may be omitted. The housing is also provided with depending side walls 4 which may be arranged in the form of a rectangle or otherwise as preferred,

The source of illumination shown in the form of an ordinary lighting bulb at 5 is supported at the top, center or otherwise conveniently arranged at or near the top center of the housing, and the side walls near the level and/or below the source of illumination 5 are open and provided with downwardly and outwardly inclined louvers or bales 'I. These louvers in the preferred form are shown as spaced apart in a direction at right angles to their surfaces by a distance which is approximately two-fifths of the width. This spacing may be varied to some extent to suit the purposes of the designer and the requirements of the trade but the spacing and proportion and angularity of the louver plates or side bailles 1 is shown to have an important influence and effect in securing the desired result of complete, direct illumination of the work with a likewise complete protection of the eyes from the glare. As shown, these louvers are inclined downwardly and outwardly at an angle of approximately 35 degrees with the vertical, though the angle may be somewhat varied to suit conditions. The entire bottom surface of the unit is open, the entire space being intersected by a series of vertical bailles 8. These as shown consist of two series 9, I0 extending across the open space at right angles to each other and the vertical baffles are Vspaced apart by a distance slightly exceeding their vertical width. The ex act spacing and width shown may be varied. The distribution of light over the work with the necessary protection of the eyes is believed to .be best accomplished as disclosed.

'I'he unit as shown in the preferred form also includes a light transmitting and diffusing plate I3 overlying the bottom baliles and side light transmitting and diffusing plates II covering the inner edges of the side banles or these diffusing plates may be otherwise suitably arranged, the important point being that all of the light released from the unit and passed between the bailies is fully and completely diffused, other diffusing means being available for this purpose. The bottom baille is almost essential to satisfactory operation.

In the lighting fixture which has been constructed embodying the features of the invention in the preferred form, the side louvers'are at an angle of fifty-live degrees with the horlzontal or thirtyafive degrees with the vertical. The spacing of the side louvers is approximately one inch and the breadth of the side louvers is two and a half inches. The inside surfaces of the housing are used as reflectors or the reflecting surfaces may be omitted, or a reflector of corrugated silvered glass or other suitable type can be put in the -upper part of the structure to reflect the light more effectively between the louvers or baliles of the side and bottom sets. The unit while it is of square cross section, as shown in Figures l, 2 and 3, may be round as lndicated in Figure 4. This latter ligure shows a lamp housing I having a relatively at conical top portion 2 and cylindrical side walls 4'. This unit is otherwise similar to Figures l, 2 and 3, or as illustrated in connection with the bed lamp to be hereinafter described, a somewhat similar unit may be rectangular with a length preferably greater than the width having side louvers on the front only or on the front and ends, or it may be of any suitable shape and arrangement. The bottom louvers may be cellular as shown in Figures l, 2 and 3, or inclined as hereinafter described, or the bottom louvers may be otherwise arranged within the scope of the invention. All the louvers and baiiles preferably have a dull finish which prevents glare due to reflection and with the housing are preferably of sheet metal or other opaque or nearly opaque material. Figures 5, 6 and 7 illustrate the invention as applied to a bed lamp or other lamps to be placed immediately over the readers head. In this instance the casing.I5 may be completely closed at the back at I6 and ends I6' and provided with a suitable support Il having a hinge or ball and socket joint or several of them as indicated at I8, and a stand 23 with an adjustable arm 23 may be provided.

The front louvers I9 are arranged similarly to the louvers 1 in Figures 1, 2, 3 and 4. The back I6 and ends or sides I6 are closed as aforesaid, the louvers being provided at the front only, The bottom baffles 20 differ from those shown in Figure 1 in that they are inclined as are the louvers or front bailles I9, the preferred angle being about sixty-live degrees to the horizontal@ or twenty-five degrees to the vertical when the unit is upright as in Figure 5. The louvers I9 are inclined forwardly and downwardly, and the bailles or bottom louvers 20 are inclined forwardly, i. e., from the back wall I6 and downwardly. The inside of the casing or housing is shown as provided with a reflector 2 I, of silvered, preferably corrugated glass overlying the bulb 22 and the inner ends of the side bailles I9 or the spaces 24 between the same are covered on the inside by means of light transmitting and diffusing plates 25. The bottom ballles 20 are provided with a bottom light transmitting and diffusing plate 26 which overlies the bailles, both plates being interposed in any convenient manner between the source of light and/or the reflector and the corresponding louvers or ballles. However, as aforesaid, the reflector and even the diffusing plates are not essential in all instances other diffusing means being available.

The bed lamp, while it is shown in strictly upbottom louvers or baiiies 20, are directed at the book, and the rays passing between the front baiiles i3 are directed forwardly into the room giving general illumination and overcoming the tendency incident to the more closely focussed reading lamps of a small intensely lighted area, the surroundings being by contrast oppressively dark. The preferred angle of tip is about 10 degrees changing the louver to an angle of 55 to the horizontal.

In Figure 8 we have shown a desk or wall lamp which has a casing 35 which is closed at the back at 36, having side baiiies 31 preferably on three sides similar to the baiiles I9 in Figure 5 and the bailles 1 in Figure 1. The bottom bailles 38 instead of being inclined as are the bottom bailles of the type of unit shown in Figure 5, are preferably of vertical arrangement so that the light is directed downwardly at the work.

This latter type of light is particularly adapted for use as a desk lamp when the desk or reading or writing table is placed against the wall, the type shown in Figures l to 4 being best adapted for use as a table and floor lamp, having particular advantages for use in the playing of games where the players are seated around a table as in card playing .or the like, illumination being effected from a central point as over the table so that a wide distribution of the light is necessary while at the same time glare must be avoided. The lighting unit or lamp described being absolutely glareless when used with bulbs of either high or low wattage, is also adapted to be placed at a sufficient height above the work to give a wide distribution of illumination, the construetion being such that the area illuminated increases rapidly with the height of the lamp above the work, also the light is fully diffused and the distribution uniform, the glare on the work being reduced to the minimum high intensities of light being available without injury to the eyes. 'I'he direct illumination of the work with the complete absence of glare gives the best working condition obtainable with artificial light, the result obtained being closely parallel in its advantages to well diffused daylight.

The description of the lighting unit as given is specific and in detail in order that the manner of constructing, applying, operating and using the invention may be fully understood, however, the specific terms herein are used in a descriptive rather than in a limiting sense, the scope of the invention being dened in the claims.

What we claim as new and desire to secure by Letters Patent is:

1. A portable lighting unit comprising a housing having a source of illumination therein, reflecting means above the source, the housing having an opening beneath the source of illumination, a glare preventing device comprising subolf the rays widely inclined from the vertical and approaching the horizontal and diffusing means for the rays which pass through both the openings.

2. A portable lighting unit comprising a housing having a source of illumination therein, rel fleeting means above the source, the housing having an opening beneath the source of illumination, a glare preventing device comprising substantially upright light absorbing baiiie plates placed apart to allow the passage of the downward rays but eliminating the sharply inclined rays, an opening in the side of the housing, downwardly and outwardly inclined baille plates with light absorbing surfaces covering said side opening to absorb the lateral rays, said plates being spaced apart to permit the rays which are downwardly inclined to pass, cutting on and absorbing the rays that are widely inclined from the vertical and those which are horizontal and approaching the horizontal, said inclined bailles being at an angle of substantially degrees to the vertical, and diffusing plates covering said openings.

3. A portable lighting unit comprising a housing having a source of illumination therein, reflecting means on one side and above the source, the housing having an opening beneath and on the side of the source of illumination opposite said reflector, a glare preventing device covering said opening comprising substantially parallel light absorbing baille plates, the center plates being disposed toward the source of illumination, and being spaced apart and distributed with substantial uniformity over the entire area of said opening to allow the passage of the downward rays and those which are substantially parallel to the plates but absorbing the sharply inclined rays which approach the horizontal, an opening in the side of the housing, downwardly and outwardly inclined baille plates with light absorbing surfaces covering said side opening to absorb the lateral rays, said plates being spaced apart to permit the rays which are downwardly inclined to pass, absorbing the horizontal rays and those approaching the horizontal and diifusing plates inthe path of and intercepting all rays which pass through said openings.

CLARENCE ERROL FERREE.

GERTRUDE RAND FERREE.

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