US2887567A - Fluorescent light fixture - Google Patents

Description

May 19, 1959 R. DAMERAL FLUORESCENT LIGHT Filed March 4,

FIXTURE INVENTOR. RA Y 0. DAME/PAL A TTORNEYS United, States Patent FLUORESCENT LIGHT FIXTURE Ray C. Dameral, Pleasant Hill, *Calif., assignor to Samuel Herst, doing business as Peerless Electric Company, San Francisco, Calif.

Application March 4, 1957, Serial No. 643,571

1 Claim. (Cl. 240--51.11)

This invention relates to lighting fixtures of the kind employed for lighting large areas such as school and oflice rooms and industrial space.

It is customary to suspend large batteries of fixtures with fluorescent tubes from the ceiling of a space to be lighted in order to obtain adequate and evenly distributed illumination throughout the space.

One difliculty that is encountered in this method of lighting is that the source, which is the tubes themselves, is too brilliant to be viewed directly with comfort and is a hindrance to good visibility. Various means, usually in the form of intricate baflles or translucent shades have been employed to combat this undesirable feature. These means are undesirable because they absorb light, increase the complexity and cost of the fixture and collect dust which is diflicult to remove and reduces the etficiency of the source.

It is the object of the present invention to provide a light fixture for elongated luminous tubes which is simple in design and directs a maximum of luminosity where it is required without producing an efiect of localized brilliance or brightness.

The manner in which this and other objects and advantages of the invention are attained can best be understood by reference to the fixture itself which is disclosed in the accompanying drawing and described in detail in the following specification.

In the drawing:

Fig. 1 is a schematic cross-sectional view of a conventional light tube of the fluorescent type which is employed in the fixture of the present invention,

Fig. 2 is a perspective View of a fixture which embodies the present invention, and

Fig. 3 is an enlarged central cross-section of the fixture shown in Fig. 2.

The lamps used in the present invention are of the fluorescent reflector type, the construction of which is illustrated in Fig. l and it is the use of such lamps in a certain position and with a certain combination of baffles that produces the advantages of the present invention. The lamp, as shown in Fig. 1, comprises an elongated glass tube shown in section at with a standard phosphor coating throughout the entire inner surface of the tube. In this particular lamp a white translucent reflector coating shown at 12 is provided beneath the phosphor coating throughout the entire length of the tube and throughout 235 of its circumference. This lamp was designed for use with the 125 area not coated with a reflecting substance directed downwardly. It is thus characteristic of the lamp to direct 75% of its output downwardly and 25% upwardly through the white reflector coating which is translucent. In Fig. l, the tube is illustrated in a position inverted from that in which it is intended for use, the position shown being that in which it is used in the fixture of the present invention.

The fixture is illustrated in Figs. 2 and 3 as comprising a pair of end plates 14 which may be castings of alumi- Patented May :19, 1959-.

num or other light weight material and which is of gen-g erally triangular shape with the apex of the triangle extending downwardly. Two of the tubes 10, such as that illustrated in Fig. 1, are supported between the end plates 14 by conventional fittings secured to the plates. These fittings and the wiring by means of which the tubes are energized are not herein illustrated as they may be of any suitable type and form no part of the present invention.

The light radiating from the tubes supported in this manner is so baflied or shielded that the major portion of the which emanates from the upper part of the tube is directed against the ceiling by which it is reflected downwardly. The lower part of the tube, as herein used, is so shielded that a minimum of brightness will be encountered by the eyes of persons occupying the room illuminated. This shielding is accomplished by a central body of generally triangular design disposed between the lamps and a pair of outer shields. The central body is formed by a top plate 15 secured as by screws or the like to lugs which project from the insides of the end members 14 and a downwardly extending curved plate 17 secured to the edges of the plate 15 by any suitable means not shown. This forms a generally triangular body with the apex of the triangle extending downwardly to a position below the bottoms of the tubes. The outer shields are curved plates 18 supported by lugs 19 on the end members 14 and also secured thereto by screws as shown. The plates 18 extend downwardly and inwardly to positions adjacent the lower portions of the tubes 10 so that only a small portion of the bottom of each tube is visible. With this small portion of the bottom of the tube visible, the maximum brightness thereof as measured for example in foot lamberts depends upon the angle from which it is viewed. For example a person standing directly beneath the lamp and looking directly upwardly from an angle of 0 as illustrated in Fig. 3 would be subjected to a brightness of 1000 foot lamberts. At the 45 angle the maximum brightness would be 600 foot lamberts while at the 60 angle the maximum brightness is only 445 foot lamberts. This is occasioned partially by the fact that the angularity increases the efiective thickness of the glass and reflector coating through which the light must pass.

It is apparent that persons working in a room seldom, if ever, look vertically upwardly at the 0 position and that the lamps are viewed mostly at or between the 45 and 60 angles. Thus the elfect of the fixture of the present invention is to produce a high degree of illumination with very low brightness which is oflensive to the eye, since the only parts of the tubular lamps which are visible are the very lower portions usually seen from a wide angle. Furthermore, the fixture is simple employing a minimum of shields or baflles with a minimum of space for the collection of dust and so arranged that they need not be removed in order to replace the tubular lamps when it becomes necessary. The entire fixture is supported in an overhead position as by conventional hangers such as illustrated at 20 and rows or batteries of fixtures are employed in the number required for the desired illumination of the area in which they are used.

I claim:

In an electric light fixture the combination with elongated fluorescent tubes of the type having a translucent reflector area throughout their length and only partially circumscribing the tubes of means to support such tubes from their ends in an overhead position with their reflector areas directed downwardly, means to shield all but the lowermost portion from vision, said means consisting entirely of a generally triangular body between and parallel to a pair of such tubes with the apex of the tri- References Cited in the file of this patent UNITED STATES PATENTS Roche Z July 30, 1929 Fletcher Oct. 10, 1950 FOREIGN PATENTS Great Britain Apr. 23, 1952 Great Britain June 17, 1953

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