US254578A

US254578A - Reflector

Info

Publication number: US254578A
Authority: US
Publication date: 1882-03-07
Anticipated expiration: 1899-03-07

Description

(No Model.)

W. WHEELER. REFLECTOR Patented Mar; 7,1882.

Inven or.

N. PETERS. Pinata-Lithographer. Washin ton, D c.

UNITED STATES PATENT OFFICE.

WILLIAM WHEELER, OF CONCORD, ASSIGNOR TO THE WHEELER RE- FLECTOR COMPANY, OF BOSTON, MASSACHUSETTS.

REFLECTOR.

SPECIFICATION forming part of Letters Patent No. 254,578, dated March '7, 1882.

Application filed September 9, 1881. (No model.)

To all whom it may concern Be it known that I, WILLIAM WHEELER, of Concord, of the county of Middlesex and State of Massachusetts, have invented a new and useful Improvement; in Reflectors; and I do hereby declare the same to be describedin the following specification and represented in the accompanying drawings, in which Figure l is an isometric projection, showing in a double forma reflector having a reflectin g-surface of such shape as would be described by the revolution about its principal axis of a curve or line of variable curvature, varying throughout its revolution by a fixedlaw, but having always the same focus common to all the variations thereof, and an ordinate common to said curve in all its variations at some fixed point of said axis, while the ordinates drawn from any other points thereof are each constantly variable throughout the whole or a part of their revolution, all as will hereinafter be shown. The elliptic curve b c d shows the form of a generatingcurve while it is above and in the vertical plane of the axis 0 0 After revolving about said axis, through the quadrant b b during which revolution every point in said curve describes aquadrant of an ellipse, of which the ordinates to said points, before and after said revolution, are respectively the conj ugate semiaxis, the generating-line occupies the position b 0 d of which the part b c is a parabolic curve. From thence-the said part b c, revolves about the axis 0 0 through the quadrant 1) b when it occupies the position of the line b 0 which is a hyperbolic curve. During said revolution every point in the said curve describes a quadrant of an ellipse, the ordimates of such points, before and after said revolution, respectively, being the conjugate semiaxis of said ellipse. The.other side or half of the reflector F is formed in the same manner, the generating-curve in the position b 0 being a parabola. The said elliptic curve I) c d,

parabolic curve b 0 hyperbolic curve b c,

and parabolic curve b 0 have the'common axis o 0 the common focus 0', and the ordinates at o -namely, o c, 0 c 0 c and 0 0 equal to each other. Said focus 0 is the focus of the reflecting-surfaces gener ed as above described.

Fig. 2 is a front or end elevati n of the same, in which the dotted curve as m w represents the four elliptical quadrants described by a point in the generating-curve half-way between the point I) and c,

Fig. 3 is an isometric view of a single reflector of the same general description as that last explained, and which differs therefrom in the. following regard, namely: The variable curve, by the revolution of which its form is described, has in its various positions the common focus 0 and a common vertex at a, or, in other words, a common ordinate at to, equal to zero.

Fig 4. represents a front elevation of the same, in which the dotted curves 1) b b b consists of the two semi-ellipses described by the point D, and the curve as m m m is composed of the two semi-ellipses described by-a point in the generating-curve half-way between the points b and c.

It is to be understood that between those quadrantal parts of the forms shown in the drawings which are upon opposite sides of the vertical plane of the axes thereof there may be inserted surfaces described by the revolution of the generating-curve through any suitable angle about a vertical axis of revolution, whereby the width of the aperture of the reflector may be varied. g

In certain cases, when it is desired that the space immediately below the reflector shall be illuminated by direct raysfrom thelight source, as well as by light reflected from the upper part of the reflector, the lower part of the reflector may be omitted, leaving only the upper part, b b b c c c d d d.

Having thfis described my invention, what 1 claim as such is as follows, viz:

l. A reflector having a reflecting-surface generated by the revolution aboutits principal axis of a curve, which is constantly variable throughout the said revolution, all being substantially as described.

2. A reflector having a reflecting-surface generated by the revolution about two or more axes, successively, of a curve which is constantly variable throughout its revolution about one'or more of the said axes, all being substantially as set forth.

WILLIAM WHEELER.

. Witnesses:

R. H. EDDY, E. B. PRATT.