US1732884A - Reflector for headlights - Google Patents

Description

Oct. 22, 1929. Q F T 1,732,884

REFLECTOR FOR HEADLIGHTS I Fil ed Feb. 14, 1927 3 Sheets-Sheet l INVENTOR. Hflkk) C. ESTZK.

0611. 22, 1929. H Q FOSTER 1,732,884

REFLECTOR FOR HEADLIGHTS Filed Feb. 14, 1927 3 Sheets-Sheet 2 o O a z 2 a 3 4 4 5 5 5 G 7 7 law/212111 87654 z| |z34.a7 SIIOIIIZIJHIFI 55c]? .Sscfl INVENTOR.

R E T S O F m H REFLECTOR FOR HEADLIGHTfi Filed Feb. 14. 192'? 3 Sheets-$heet Patented Oct. 22 1929 UNITED STATES PATENT OFFICE HARRY O. FOSTER, 0F CONNERSVILLE, INDIANA, ASSIGNOR TO INDIANA LAMP COR- PORATION, OF CONNERSVILLE, INDIANA, A CORPORATION REFLECTOR FOR. HEADLIGHTS Application filed February 14, 1927. Serial No. 167,998.

This invention pertains to a reflector particularly adapted to be used in connection with vehicle headlights.

The main feature of the invention resides in the provision of a reflector formed of one piece of metal having its reflecting surface comprised of a plurality of parabolic sections, each of which is of a different focal length, said sections merging into each other so as to avoid any substantial break between their ad joining surfaces, whereby the beams of light projected from each of said surfaces Wlll form a combined pattern such as to comply with the present day requirements, as will hereinafter be more fully set forth and described.

Another feature of the invention resides in the provision of vertical flutes or flats of Varying widths in each of the reflecting surfaces for spreading the light rays projected therefrom and distributing the same in such fashion as to form a combined beam of the desired or required spread, without, the re quirement of the usual diffusing spreading lens of the prismatic character. Thus a headlight embodying this reflector may be employed with a plain clear glass lens or closure.

Still another feature of the invention resides in the provision on one of the reflecting surfaces, the lower one as herein shown, of a plurality of fiat surfaces formed by combinin'g horizontally-extending flats with the vertically-extending flats. This formation of the reflecting surface so disperses the rays projected therefrom as to reflect them over substantially the entire pattern, or thegreater portion thereof so as to eliminate dark spots or shadows which may occur by reason of the merging of the light beams from the other sections, or defects in the commercial reflector. v

A reflector having the above characteristics, and constructed ashereinafter more fully set forth and described will project a beam having the desired lateral spread cut-off at the top, and by reason of the relative angular.

displacement of the sections, will project the light below a horizontal plane through its axis, the central portion of the beam being of maximum intensity for projecting the beam at the greatest distance down the road, the lower and lateral portions of the beam shading off toward the bottom and sides. Furthermore, by reason of this construction, a double filament bulb may be used in such fashion as to raise or lower the beam to the desired extent without noticeably affecting the light pattern produced therebyf The full nature of the invention will be understood from the accompanying drawings and the following description and claims.

In the drawings, Figure 1 is a front elevation of the reflector. Fig. 2 is a central vertical section therethrough. Fig. 3 is a sectional illustration of the formation of the reflecting surface of the upper section A adjacent its connection with section B. Fig. 4 is the same with respect to section B adjacent its connection with section C. Fig. 5 is a sectional illustration taken on a horizontal plane through the center of the reflector showing the formation of the reflecting surface of section C. Fig. 6 is the same as Figs. 3 and 4 with respect to section D adjacent its connection with section C. Fig. 7 is a diagrammatical illustration showing the light pattern or distribution of the rays. Fig. 8 is a diagrammatical illustration of the combined parabolic sections forming the reflector shown in Figs. 1 and 2.

In the drawings there is shown a reflector 10 having the usual annular flangell and opening 12 in the center thereof for a lamp bulb, said reflector being formed of a plurality of parabolic sections in a vertical plane associated together, comprising the sections A, B, C and D.

The reflecting surface A is provided with a plurality of flats 13 and 14, as shown in Figs. 1 and 3. Said flats extend vertically when the reflector is properly mounted, there being one centrally-positioned flat 13 on each side of which there are flats 14 of a greater width. The reflecting surface B is provided with a plurality of vertically-extending flats 15 of substantially the same width throughout the entire section. Section C is formed of-a plurality of vertical flats 16 and 17, the flats 16 being of less width than the flats 17. Section D is provided with a plurality of vertical flats 18, 19, 20 and 21, increasing in width from the center toward each side. Said section D also has horizontally-extending flats of a uniform width, whereby the parabolic surface thereof is broken up into a plurality of substantially flat rectangular surfaces which will spread the beam projected thereby in a yertical plane as well as a horizontal plane.

Referring to Fig. 8 and considering the sections as intercepted by a vertical plane through the center of the reflector, section C comprises. a parabola with a focal length less than D and greater than sections A and B as shown herein 1 and 5/16 of an inch, and having its axis indicated by the line XX with its focal point at F, the projection of continuation of the curve being indicated by c-0.

Section B has a focal length of 1 and 3/16 of an inch as shown herein, which is less than sections C and D but/greater than section A, its focal point F being positioned close, but slightly to the rear of the focal point F on its axis X-X. As shown it is divided from section C on the line indicated by YY, and is positioned forwardly of section C .093 of an inch. Both sections B and C have the same axis XX.

Section A has a focal length of 1 and 1/32 of an inch, which is less than any of the other sections, and it is positioned immediately above section B, having its focal point F lying on the line XX to the rear of the focal point F". This section is tilted downwardly approximately three degrees so that its axis will extend downwardl with respect to the axis XX as indicate by X i Section D has a focal length of 1 and 3/8 of an inch, which is greater than that of the other sections. It is positioned at the bottom of the reflector below section C. Its focal point F is positioned on the line XX slightly in front of the focal point F and it is tilted downwardly approximately one degree so that its axis extends on the line XX.

In 'emplo ing the reflector with a double filament bu b, the bulb is so positioned'that the lower filament will lie approximately upon the axis XX between the focal points F and F while the upper filament will be positioned substantially on the line XX.

As shown in Fig. 7, a source of light positioned in the focal area of the reflector will produce a pattern on a vertical screen at about 25 feet, wherein the section A throws the lowermost pattern havin .the greater spread, as indicated by sec. A on said pattern, when the reflector is in horizontal position, extending from three to six degrees below horizontal and having a spread of about thirty-two degrees or sixteen degrees on each side of the center. This forms the lowermost and widest section of the beam due to the three degrees downward inclination of the reflecting surface and the relatively wide vertical flats. The beam projected by section B, which will partially be superimposed upon the attern of section A, extends from one to six egrees below horizontal and has a spread of about twenty-six degrees, or thirteen degrees on each side of the center.' This is due to its horizontal position a distance above the center of the reflector with its focal point very slightly belowithe line X -X, suflicient to drop the beam about one degree, its spread of twenty-six degrees being caused by the flats 15.

The pattern rojected by the principal or center section is more concentrated, extending from horizontal to about three and onehalf degrees below horizontal, having a maximum spread of about twenty degrees, ten degrees on each side of center, as illustrated in Fig. 7 by sec. C. The greater intensity of light will be projected from this substantially central section 0 and the light will be "spread over a smaller area than the spread from the other sections so as to be more concentrated, the smaller flats 16 at the center of the section causing the beam to spread laterally only to a slight extent, as shown herein about five and one-half de rees on each side of center, Whereas the wide flats 17 extend or spread'in a narrower form about four and one-half degrees further on each side of center. The lower or bottom section I) distributes its beam over a much greater area than any of the other beams, from horizontal or zero to about six degrees below horizontal, having a lateral spread of only about nine degrees on each side off center, as indicated by sec. D. This is the result of the flat surfaces caused by the combined vertically and horizontally extending flats which effect both a vertical and a horizontal spread. The rays coming from this lower sectionand overlapping all the other sections act to iron out any dark spots or shadows and smooth out the beam.

As the most desirable light should have its greatest intensity at about one and one-half degrees below horizontal so as to strike and illuminate the road more intensely at the proper distance from the vehicle, it will be noted in Fig. 7 that the rays from the three principal beams are superimposed in this area, thus effecting the desired intensity.

The invention claimed is:

1. In combination with a source of light, a reflector adapted to receive light rays therefrom and to reflect said lightrays so as to form a light pattern upon an object placed in the path of said rays, said reflector having a plurality of reflecting sections substantially parabolic in general contour including a section having its axis inclined to direct its beam to a portion only of the light pattern and having a plurality of sub-sections substantially the beam therefrom flat in the horizontal direction formed across its surface for lateral diffusion of light, a second section having its axis inclined to direct its beam to a different portion of the li ht pattern and having a plurality of wider su -secti0ns substantially fiat in the horizontal direction formed across its surface for wider lateral light diffusion, and athird section having a plurality of sub-sections sub stantially flat in both vertical and horizontal directions for both vertical and lateral light diffusion and having its axis inclined to direct its beam over substantially the entire light pattern in the verticaldirection whereby the intersection of the beams of the first two sec tions is rendered unnoticeable.

2. In combination with a source 'of light, a reflector adapted to receive light rays therefrom and'to reflect said light rays so as to form a light pattern upon an object placed in the path of said rays, said reflector having a plurality of reflecting sections substantially parabolic in general contour including a section having its axis inclined to direct the light pattern and having a plurality of sub-sections substantially flat in the horizontal direction formed across its surface for lateral difl'usion of light,ia second section having its axis inclined to direct the beam there from to the lower portion of the light pattern and having a plurality of wider subsections substantially flat in the horizontal direction formed across its surface for lateral light diffusion wider than said first section, and a third section having its axis inclined to direct the beam therefrom over substantially the entire light pattern in the vertical direction and having a plurality of subsections substantially fiat in both vertical and horizontal directions for both vertical and lateral light diffusion, whereby the beam from said llih lid

lastmentioned section renders the intersec tion of the beams from said first-mentioned sections unnoticeabla.

3. In combination with a source of light, a reflector adapted to receive lightrays there from and to reflect said light rays so as to form a light pattern upon an object placed in the path of said rays, said reflector having a plurality of reflecting sections substantially parabolic in general contour including a section having its axis inclined to direct the beam therefrom to the upper por-- tion of the light pattern and having a pin rality of sub-sections substantially flat in the horizontal direction formed across its sur face for lateral diffusion of light, a second section having its axis inclined to direct its.

beam over substantially the entire light pattern in the vertical direction and having a plurality of wider sub-sections substantially flat in the horizontal direction formed in its surface for Wider lateral light dili'usion, a third section having its axis inclined to direct to the upper portion of its beam to the lower portion of the light pattern and having a plurality of sub-sections substantially flat in horizontal direc tion formed in the surface thereof wider than those in the surface of said second-mew tioned section for lateral light diffusion Wider than said second-mentioned section, and a fourth section having its axis inclined to direct its beam over substantially the em tire light pattern in the vertical direction and having a plurality of subsections sub stantially flat in both horizontal and vertical directions for both horizontal and vertical light difiusion, whereby the intersection of the pattern of the first three mctions is rendered unnoticeable.

In witness whereof, I have hereunto aflixed my signature.

' HARRY C. FOSTER.

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