US239312A - Reflector - Google Patents

Description

(No Model.) A

- C. F. BRUSH.

Reflector. Y

No. 239,312. Patented March 29,1881.

INVENTUM ER. AsHINGroN vUNITED' STATES PATENT OFFICE.

CHARLES F. BRUSH, OF CLEVELAND, OHIO.

REFLECTO R.

SPECIFICATION forming part of Letterslatent No. 239,312, dated March 29, 1881.

Application filed August 6, 1880. (No model.)

To all whom it may concern:

Be it known that I, CHARLEs F. BRUSH, of Cleveland, iu the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Reflectors; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enable others skilled in the art to which it pertains to'make and use it, reference being had to the accompanying drawin gs, whichform part of this specication.

My invention relates to reflectors for electric and other lights, and has for its object the suppression of the direct or unrellected light issuingfrom the luminous source, without interferin g materially with the reflected rays. The desirability of this suppression is very apparent when electric lights are used with parabolic or other reflectors on board ships. Here the object of the reflector and light is to illuminate distant objects while the ship remains in comparative darkness, so that the pilot may clearly see the distant objects illuminated without being himself blinded by the light. When an electric light is used with even a very deep pariibolic reiiector in the ordinary manner, the wide cone of unreflected light escaping from the mouth of the reflector illuminates the mist, which is always present in greater or less quantity in the atmosphere near the surface of water, so as to present the appearance of a luminous fog-bank of greater or less den sity and of large size. The water is also rendered distinctly luminous where the light strikes it, especially when rough. This luminosity ofthe water and atmosphere is very annoying to the pilot, often making the electric light an annoyance rather than a benefit; but when the cone of unrelected light is suppressed these evils disappear, and the great utility of the light becomes manifest. The unretlected light may evidently be suppressed by adapting a tube of suitable size (cylindrical or slightly conical) to the mouth of the reflector and extending it a sufficient distance forward; but it is equally evident that this method is impracticable.

I accomplish my object by placing a short tube of comparatively small diameter very near the light, with its axis coincident with that of the reflected beam.

In the drawings, Figure l shows a crosssection through its axis of an ordinary parabolic reflector provided with my device. Fig. 2 shows afront view of the same. Fig. 3 shows a shallow spherical reflector provided with my device. Figs. et and 5 show disks substituted for the tubular device.

A, Figs. l and 2, is a parabolic reflector, provided with openings in the usual manner, through which the carbons b b of an electric lamp pass, uniting at or near the focus c of the reflector.

B is a tube of thin metal, open at both ends, and having its axis 4coincident with the axis of the reector. This tubeis placed sufficiently near the luminous point to obstruct the cone of light a c which would otherwise issue .unreected from the parabola, but not suiiiciently near to intercept rays of light which would fall within the reliector. The tube Bi evidently does not interfere with the reflected light, since the latter may all pass through and outside of it. The unreected light issuing from the tube is so slightly divergent as to be unobjectionable. Y

The tubeB may be supported in position by any suitable means, one method being shown in thc figures. In practice I prefer to attach the tube to guides through which the carbons b b pass, so that the relative position of the tube and luminous center may remain constant,

" while the position of the light is changed backward or forward to make the reflected beam slightly divergent or parallel, as may be required.

Fig. 3 shows my device adapted to a shallow reflector. Here the tube B necessarily extends slightly back of the carbons, and is provided with suitable openings through which the carbons pass, as shown.

The tube B should nothave a reflecting surface inside, because, if reliecting, the cone of light entering it will, after several reections, emerge as the same cone diminished in intensity, however, by the reflections it has undergone.

Evidently a small disk suitably placed would oppose the uureflected cone of light, Figs. l and 2, as well as does the tube B; but it would also intercept more 'or less of the reflected light, according to its size. If made very small this loss of light would not be no- IOC ticeable, butthe necessary proximity of the diskto the luminous point and the mal-adjustment attending a slight change in position of the latter render its use objectionable.

Fig. 4 shows a disk, e, substituted for the tube B, Fig. l.

Fig. 5 shows a disk and tube, e, substituted for the tube B, Fig. This disk e, While it may be employed as an inferior substitute for the tube, I do not consider to be an equivalent thereof. I have merely referred to the disk in this specification by Way of explanation; but as it is my intention hereafter to make separate application for Letters Patent upon said disk, I do not intend, by anything disclosed in this specitication, to waive any right ot' hereafter applying for and securing a patent upon the disk e referred to.

What I claim ist The combination, with a concave reflector, of a cut-oft' tube having a non-reeotin g inner surface, said tube located in such proximity to the light or ame as to intercept and cut off the direct rays of light, substantially as shown and described.

In testimony whereof I have signed myname to this specification in the presence of two subscribin g witnesses.

CHARLES F. BRUSH.

Witnesses:

LEVERETT L. LEGGETT, JNO. CROWELL, Jr.

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