US1381103A - Reflector - Google Patents

Description

W. T. BLACKWELL.

REFLECTOR.

APPLICATION FILED MAR.27,1919.

Patented June 14, 1921 INV ENTOR I ATTORNEY WILLIAM THOMAS BLACKWELL, OF VERONA, NEW JERSEY, ASSIGNOR TO WESTING- HOUSE LAM]? COMPANY, A CORPORATION OF PENNSYLVANIA.

anrmacron.

Specification of Letters Patent.

Patented June Ml, 19211.

Application filed March 27, 1919. Serial in. 285,463.

To all whom it may concern:

Be it known that 1, WILLIAM THOMAS BLACKWELL, a citizen of the United States, and a resident of Verona, in the county of Essex and State of New Jersey, have invented a new and useful Improvement in Reflectors, of which the following is a specification.

This invention relates to reflectors, and, more particularly, to those useful in' industrial lighting and adapted to be used with an incandescent lamp.

At present the most common form of reflector used in industrial lighting is a direct lighting fixture of the porcelain enameled steel type, having one or more reflecting surfaces. This type reflector recommends itself for this special field of illumination because of its durability and the elimination of glare, although the efliciency of such a reflector is but approximately of the total light flux of the incandescent lamp. The loss of 30% in light is caused bythe absor tion of the reflecting surface.

lass reflectors, although they give a certain amount of diffused light and'a somewhat higher efficiency than. an opaque reflector, have been found unsuitable for industrial lighting because of their liability to breakage through accidental contact with foreign objects, and because they do not effectively shield the eye from glare.

An object of the invention is the provision of a composite reflector of rugged construction, which produces a direct lighting eflect, having an intensity substantially equal to a reflector of the porcelain enameled type, and also gives a diflused lighting eflect such as is obtained by a less reflector.

Another object of the invention is the provision of a reflector having a greater light reflecting efliciency than the present forms of metallic reflectors used in direct lighting, and at the same time possessing the advantages thereof.

I accomplish theseobjects by providing a composite reflector, the-lower part of which may be comprised of porcelaln enameled steel and the upper portion constituted of a light diffusing material, such as glass. I have found that a reflector, embodying this construction, has an efficiency of substantially Other objects of the invention relate to the combination and construction of parts which is adapted to engage the lower portion of the light difl'using element 2. There is provided a retaining member 5, which may consist of a thin piece of sheet metal, or the like, suitably attached to the inner surface of the skirt 3, and in cooperative posi- .tion with the bent-over portion 4, so that the element 2 may be firmly held in the groove formed by the parts 4 and 5. The retaining member 5 may be pressed into contact with the light diffusing element 2 by any suitable instrument, care being taken not to fracture the same.

The light diffusing element 2 may consist of any kind of glass such as opal, opalescent, prismatic, and the like. The amount of diffused light obtained will vary with the density of the glass used, which is in accordance with the well established principle that the greater the density of the glass the less the difi'usion of the li ht. It is likewise true that the more ligh diffused by the element 2, the less light there will be reflected, and,

vice versa, the more light reflected, the less light there will be difl'used. It, therefore, 7

follows that the kind and density of the glass selected for the element 2 will be controlling in the amount of light diffused or reflected, and may vary under diflerent service conditions. It is preferable that the ele 'ment 2 be of more than one contour as better flange 6 and a resilient ring 7 which is confined in a recess located at the base of the fitter 1. If des1red,-a-washer 8, of fiber or flectors.

like substance, may be placed intermediate the contacting edge of the glass element and the ring 7. lt is obvious that the fitter 1 may be made of sheet metal or a fibrous composition, since it performs no function in the reflection of the light.

It is obvious that the reflector contemplated by my invention, aside from its reflecting qualities, may be regarded as of the so-called knocked-down construction. For example, the reflector illustrated may have the fitter 1 detached therefrom prior to its use by the customer, which feature permits the reflector being placed in a smaller package than if made of a single part. Still further advantage may be taken of this knocked-down construction by packing the glass element 2 within the skirt 3, the latter affording protection for the former. Such a method of shipping is obviously feasible inasmuch as the elements 1, 2, and 3 have a telescopic relation to each other, and can readily be assembled by theuser.

From the above description it will be ap parent that a reflector embodying my invention will give a certain amount of light in the upper hemisphere, and, at the same time, give a light in the lower hemisphere substantially equal in intensity to that obtained from present forms of metallic re-.

Because of this feature, my reflector may be found useful for purposes other than in industrial lighting. It will also be noted that the telescopicconstruction of my reflector makes it attractive to the trade from the standpoint of business economies. I

While I have herein shown and particularly described a preferred embodiment of my invention, ll do not wish to be limited to the precise details of construction illustrated, as changes may readily be made Without departing from the spirit and scope of the invention.-

What is claimed is:

1. A composite reflector comprising a por tensity of the light obtained from an entirely I opaque reflector having a similar configuraaeeaioa of the edges of the said skirt portion, and a supporting fitter member adjacent to said translucent portion, the design and the glass constituting the translucent portion being such that the distribution and intensity of light in the lower hemisphere is substantially equal to the distribution and intensity of the light obtained from an entirely opaque reflector having a similar configuration, while the light cast in the upper hemisphere is an appreciable percentage of the total lighting efliciency of the reflector.

3. A composite reflector comprising a lower skirt opaque reflecting portion provided with a deep cutofl angle, a translucent portion adjacent to said opaque portion, the said translucent portion functioning as a light diffuser and as a reflector, and a fitter member adjacent to said translucent portion, the design and the material constituting the translucent portion being such that the distribution and intensity of the light in the lower hemisphere is substantially equal to the distribution and intensity of the light obtained from an entirely opaque reflector having a similar configuration, while the light cast in the upper hemisphere is an appreciable percentage of the total lighting efliciency of the reflector.

a. A composite reflector comprising an opaque reflecting portion, and a translucent portion adjacent thereto, the said translucent portion functioning as a light diffuser and as a reflector, the materials, configuration and relation of said portions being such that the distribution and intensity of the light in the lower hemisphere is substantially equal to the distribution and intensity of the light obtained from an entirely opaque reflector having a similar configuration, while the light cast in the upper hemisphere is an ap preciable percentage of the total lighting efficiency of the reflector.

In testimony whereof, l have hereunto subscribed my name this twentieth day of March, 1919.

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