US1723535A - Headlight - Google Patents

Description

Aug. 6, 1929.

E. J. WHALEN HEADLIGHT Filed March 25, 1927 2 Sheets-Sheet l 7% 3, M/ x W W1 M/k g A i kgk/ I I. 3 INVENTOR.

A TTORNEY5 Aug. 6, 1929. I E. J. WHALEN HEADLIGHT Filed March 25, 1927 2 Sheets-Sheet 2 I IINVENTOR.

ATTORNEYS.

Patented Aug. 6, 1929.

UNlTED STATES PATENT OFFICE.

EDWARD J. WHALEN, 0F SYRACUSE, NEW YORK, ASSIGNOR TO REDIRECTED LIGHT CORPORATION OF AMERICA, OF SYRACUSE, NEW YORK, A CORPORATION ,OF NEW YORK.

HEADLIGHT.

Application filed March 25, 1927. Serial No. 178,421.

This invention relates to headlights and particularly to headlights which are ellipsoidal or equivalent shape, and has for its object a particularly simple means for re- (lirccting and hence controlling most of thelight whereby the light is projected in a beam or in lines approaching the horizontal or lines which are inclined more or less out of the horizontal in contradistinction to out of the vertical.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawings in which like characters represent corresponding parts in all the views.

Figure 1 is a diagrammatic View of a headlight embodying my invention.

Figure 2 is a horizontal sectional view on the horizontal plane of the axis of the headlight.

This headlight comprises generally, an ellipsoidal body or a body which has an internal, cylindrical, ellipsoidal surface, the body having a light projecting opening at its front end, a source of light arranged substantially in the rear focus of the ellipsoidal body, and one or more preferably, a plurality of rearwardly presented ellipsoidal reflecting surfaces, each having its foci located respectively in the focus at the rear end of the body and in the ellipsoidal surface of the body in the rear of the focal plane. The headlight also includes one or more ellipsoidal surfaces located in the rear of the focal plane and below the horizontal axis of the body, and having one of its foci located in the rear focus of the ellipsoidal body, and its other focus located below the horizontal plane of the axis of the body and at the front end of the body.

As is well known to those skilled in the art, the light reflecting from an ellipsoidal surface when the source of light is in one focus of the ellipsoidal curve, passes through the other focus.

My invention is based upon this property of the ellipsoid and has for its object the formation of a beam of light by locating a plurality of rearwardly presented ellipsoidal surfaces within theprincipal ellipsoidal reflector or body, each having one of its foci coincident with one of the foci of the principal ellipsoidal reflector or body, and its other focus located in the ellipsoidal surface of the principal reflector or body so that all light from all the ellipsoidal reflectors passes through or near the secondary focus of the principal. reflector or body. As the foci of ellipsoids are generally designated F, F, this scheme of using the letters F and F will be followed throughout this specification and the secondary foci for the auxiliary reflect .ing surfaces will be designated with a small letter 7" or a small letter with a coefficient.

1 designates the body, which may be of any suitable form, size and. construction, it having a light projecting opening 2 at its front end in which a suitable glass plate 3 is located. F and F designate respectively the foci of the ellipsoidal curve of the body or principal reflector. The line AA designates the axis of revolution of the principal reflector and. the line lP--P the fo cal plane.

t designates the lamp bulb, the filament of which is located as near possible in the focus F, this lamp being supported in the body 1 in any suitable manner.

5, 6, 7, 8, 9 and 10 designate respectively a series of ellipsoidal, rcarwardly presented reflecting surfaces preferably located in the lower half of the body below the horizontal plane of the axis A A, each of these reflecting surfaces having the focus F as one of its focal points and having the other focal point f, f f f 7"", 7' located in the ellipsoid al surface of the principal reflector or body 1 in the rear of the focal plane P-P. Obviously, the surface 10 located farthest from the focus F has its secondary focus 7" located nearer the axis AA than the surfaces 5, 6, 7, 8 and 9, and the foci f, 7, f progress from the portion of the ellipsoid to the focal plane in toward the axis A A.

In order to utilize the light directly below the horizontal plane of the axis of revolution A A, the rays projected downwardly and rearwardly from the source of light at F, an ellipsoidal reflector is located. below said plane AA and in the rear of the lamp or the focus F and the focus F is one of the foci of this reflector 11 and the other focus F is located at the front of the lamp below the horizontal plane of the axis A A. Thus, the

. are so located that the projections therefrom practically overlap each other or one falls upon or is coincident with the others. Only a very small percentage of the emitted light strikes the glass 3 directly and considerably over 90% of the emitted rays strikes the reflectors, and hence is redirected into the desired portions of the beam. By suitably varying the position and number of the reflecting segments in the lower half of the reflector. a sharply defined cut-off is secured in the beam without the absorption or screening off of any of the emitted light. Thus, a more intense illumination is secured in those por tions of the beam where it is of most use, by merely redirecting the light from those portions of the beam where a high intensity is not desired.

The ellipsoidal form of reflector, with major axis about twice the minor, furtheris behind the focal plane.

more restricts the dir ct illumination obtained from the lamp filament to a small fraction-of the total light emission.

he reflecting segments in the lower half of the reflector are compound cylindricalellipsoidal in form with the axis of revolution coincident with the axis A-A of the reflector and the filament center forming one focus of the ellipsoids. For all of these segments lying in front of the focal plane of the lamp, the second generating focus f, 7, f f f 7" The surface 11 behind the focal plane and below the axis of revolution A-A has one of its foci coincident with the focus F and the other below the horizontal plane of revolution AA so that the axis of revolution of the ellipsoid of the snrface 11 is inclined at a small angle downwardly and forwardly out of the horizontal. A fixed focus lamp is used, preferably placed in a vertical instead of the usual hori'/.ontal position. Thus, the loss of reflecting surface to the lamp base is taken from the least useful redirected wide angle line, instead of from the more important main beam. However, the obstruction due to the use of a lamp located in the rear focus may be eliminated by locating the lamp in the front POI'tlOll of the body and focusing the light therefrom in the focus F by a reflector and .lens or by locating the light in the focus of a secondary ellipsoid,

the other focus of which is located at F of the principal ellipsoid. In either case, the focal point is considered the location of the source of light.

V hat I claim is:

A headlight comprising a. principal ellipsoidal reflector having a light projecting opening at its front end, a second ellipsoidal reflector located in the rear of the rear focus of the principal reflector below the horizontal plane of the axis of revolution of the body. the second reflect-or having its rear focus coincident with the rear focus of the principal reflector and having its front focus located at the front of the principal reflector below the horizontal plane of the axis of revolution of the principal reflector and a source of light located substantially in the fear focus,

In testimony whereof, I have hereunto signed my name. at Syracuse, in the county of Onondaga, and in the State of New York, this 8th day of March, 1927.

EDXVARD J. \VHALEN.

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