US149555A

US149555A - Improvement in reflectors

Info

Publication number: US149555A
Authority: US
Publication date: 1874-04-07
Anticipated expiration: 1891-04-07

Description

A. WILHELM. Beieciurs;

Patented April 7, 1874.

ANo.149

UNITED STATES PATENT OFFICE I |MPR1ovEMENT IN REFLEcToRs..

Specification forming part of Letters Patent No. 119,555,

dated April 7, 1874 application filed December 2, 1873.l

to the accompanying drawings vmaking part of this specification, in which- Flgures l and 2 are vertical sections through the center of the relector.

Similarlts' of reference indicatel corresponding parts in the two figures.

The object of the invention is to improve that class of light-reflectors which are suspended horizontally from the ceilings of churches, halls, depots, places of amusement, Sto., and are designed to reflect and diffuse the rays of light coming from aseries of burners downward and outward, so as to perfectly illuminate these places.

The form of reflector generally employed is that of a frustum of a cone inserted into the ceiling, or a cone suspended in the center of the frustum.` These reectors are the so-styled double-cone reflectors. They have two serious defects, which, by my improvement, I design to remedy, besides producing a more perfect and stronger reflector than heretofore made.

The `first defect of the so-called double-cone reiiectoris, that the frustum and inner cone are two distinct parts, their reiieeting surfaces being separated, leaving an open space around the upper part of the reflector. The reflector may be suspended from the inner cone, or from the circumference of the frustum; but in either case it necessitates the connection of the frustum with the inner cone by strong braces of wire or strips of metal. The opening caused by the separation of the two reiiecting-'surfaces around the top of the reiiector causes a greater loss of light than is absolutely necessary. f

The second defect of the so-called doublecone reflector is, that the form of the reflector does not give the constructer sufficient control over the rays of light to illuminate a given space evenly, or obtain the best results with a given number of burners, as he would have if the reliecting-surfaces were so curved as to positively reflect the light where it is needed, and thus overcome the before-named second defect of the old-style refiector, thereby producing a correctly-formed and strongly-constructed light-reiiector.

Referring to the drawings, A represents the inner pendant; A A, the central basin, and A" Al the outer1 rim. The dotted lines show the manner of constructing the reiiectingsurfaces, and the resultant direction of the reiiected rays of light coming from lights placed on the focus-.line F F.

In Fig. l I construct the reflector of the inner pendant A', the central basin A A, and the outer rim A A. The inner pendant A is formed of the convex curves cv b c' b. At b b begins the central basin A A, which is formed of the concave elliptic curves b a b b a b, and at bb begins the outer rim A A, which is formed of the convex curves b c b c, and is pendent toward and below the ring of lightsv placed on the focus-line F F of the basin part A A. All the curves forming the different parts of the body of the reflector are continuous of each other. The convex curves are segments of circles, and the concave curves are segments of ellipses. FF is the focus-line of the basin partA A ofthe reiiector. The rays of light (represented in the drawing by the dotted lines) falling on the convex curves c b c b c b c b are divergingly reiiected downward7 and those rays falling on the concave elliptic curves b a b b c b are reflected convergingly to the other focuses of the ellipses, and, passing through those focuses, diverge downwardly.

It will be seen by the direction of the dotted lines, representing the reflected rays of light coming from lights placed on the focusline F F of the basin part A A, that all the light is reliected downwardly within the angles c F c c F c; consequently all the light is utilized and reflected in the space which is to be illuminated.

It will also be seen that by making the inner pendant A', the central basin A A, and the outer rim A A continuous of each other, a strongstructure is produced, and the reflector can, therefore, be suspended either from the inner pendant without extra support on `the circumference, or from the outer rim or circumference Without eXtra support for the inner pendant. p

Various modifica-tions may be made. In Fig. 2 the inner pendant or projection A', the central basin A A, and the outer rim A A pendent below the focus-line F F of the basin part A A, are formed of the concave elliptic curves c a c c a c. of a single curve, the distinctive features of the different parts is not so deiined, as shown in Fig. 1. Yet the principle oi' a continuous rciectingourved surface, forming parts A', A

` A,'and A A, is also plainly demonstrated in Fig. 2.

It will also be seen that by the dotted hues, representing rays falling on the refl ectin g-surfaces c a c c al o of the reflector, they are converging to the other focuses of the ellipses of which the curves are segments, and, passing through the focuses, diverge downwardly. Thus the light is utilized in the same manner as shown in Fig. l, and the general structure of the retlector is equally as strong, and the same in principle.

The contour of the reflector may be circular, oblong, oval, or polygonal.

I am aware that reflectors have been con- As these parts are formed` structed of an outer and inner part, as shown in the'doublecone reector, or in the reflector constructed for a light-house; but in both of these reflectors the inner and outer parts are separated and not continuous. In the lighthous'ereector the reilecting-surfaces of the outer and inner parts are formed of the parabolic curve, and all the rays reected from it are reflected in parallel lines downward; but by the construction of my reflectingsurfaces the light will be diffused downward and outward.

. Having shown and described the particular advantages of my improved form and con-y struction for a reflector, what I claim as my invention, and desire to secure by Letters Patent, is

A ceiling-reliector having a continuous curved reecting-surface, the same consisting of an inner pendant or projection, a central basin of elliptical form in vertical section, and an outer rim pendent toward or below the lights, in combination with the ring of lights placed on the focus-line of the basin portion of the reector, for the purpose herein set forth.

Witnesses: AUGUST WILHELM.

JOHN A. WIEDERSHEIM, G. S. HETHERINGTON.