US1577352A - Headlight reflector - Google Patents

Description

March 16 1926. -1,577,352

M. W. CAUGHLAN HEADLIGHT REFLEGTOR Filed May 13, 1925 2 Sheets-Sheet 1 N A L H G U A C w M.

Mam-.h 16 1926.

HEADLIGHT REFLECTOR Filed May 15, 1925 2 Sheets-Sheet 2 a '11 il lill liti,

einen eterne retour ourlet..

HEADLIGHT REELEC'TE.

Application tiled May 13, i925. Serial lilo. 29,938.

to improvements on the structure shown in' my elo-pending application entitled loin-- poundreflector, tiled January 19, i925, Serial No, 3335.

i lihe principe/tl ob'ject sought in my application above referred to Wits thev attainment of en ideal distribution of light from u reflecting!y surface es adapted for use in a lamp for illuminating `the road with an ideal field for Vehicle use, projecting the light from one portion ot e compound refiector in e concentrated and subetantinlly hoi-i zontsil beam, sind from another portion o'l the reflector in e, relatively less intense and laterally divergent and downwardly-directed beam.

'llo obtain these results l employed u coinpound reflector, Within which is positioned a lomp, or other light Source; the upper portion of the reflectorv above the horizontal plane passing through the lamp consisting titl of substantially a hemi-ellipsoid ot revolution whose major eine parses through lthe lamp and one of whose foci is coincident with the lamp; and the lower portion of the reflect/or is formed ot a series oi diminiehint ellipees whose lmejor axes are parallel and in the saine Vertical plane es the major axis of the aforesaid ellipsoid of revolution and Whose foci remote troni the lump lie on a,

" vertical line; und whose other t'oci lic on a.

-pnraboln pa' singy through the lamp.

application aforesaid, or with other reflectors, it being possible to use this auxiliary or condensing reflector in various relations to other reflectors, or with modifications of my compound reflector.

The invention consists of the parts end the construction and combination of parts` as hereinafter more fully described and claimed, having reference to the eocornpeny` ingr drawings in whicbz- .,igure l 1e a sectional plan on the horizontal Aplane passing through the light source, showing my invention in combination with the compound reilector of my copending application.

Figure 2 isaN side elevation of the above combination.

Figure 3 is a side elevation of my con- (lensing reflector.

Figure t is a front elevation of my condensing' reflector.

Figure 5 is a. diagrammatic plan View of the exterior surface of my condensing' reflector #how-ing its development Figure tl is another diagrammatic plan View of the same.

Figure 7 is a horizontal Section on plane Vil- VIL of Figure 3.

Figure 8 is similar to Figure 7, but shows tbe outer nrc es hyperbolic instead of parte bolic.

Throughout the figures, similar numerals refer to identical parts, or parts 'li"nction'n"' in the same manner.

lt will be Seen by reference to lli'rurev l and 2 and as particularly explained in detail in my tto-pending applieation'that above the major horizontal axis M mv compound rclector is a herni-ellipsoid of revolution about Said exis, and that from said axis downward the lower main reflector is elliptical on all horizontal parallel planes. 6, 7, 8, and 9 and parabolic on all vertical planes as defined by its intersection by 'i vertical pencil ot planes rotated about the vertical axis F--F. lt then followe necessarily tbatligbt rays R ernanatincr from F, the focal point of the reflector. and also the focus common to ell the ellipses and parabolas involved, will be reflected on parallel horizontal planes, converging and crossing on the line FC- "8, the locus of the remote foci of all the elliptical arcs involved.

.ioni

To carry out the object of my present i."

' line, several of the vert-ical inveniion end restrict the Sonie oi :biiese rays after en c. originelly el, lieg) and ilierelay' pr beam oi greater intensity in the cei'ierlllil, i' insert! adjacent lo the been opening; 'it' 'ne com' ouml reflector the condensing' relecior s snown in side elevation lligrre il, iront elevation Figure Il, enclin ligin'ef- 7 end l. Figure inflicntes plan illie diminishing paraboles of lle exterior reiui ing surface. Fin'. G shows in planfin flolvleci planes, Willi axis ll"-F which form parabolic eres on lic snrl'ece of the reflector es also shown ny dotted lines in Fig. Il.

Fig. 'i is e plane section on plone lll-Vlfl, of Fig. 3, showing the exterior v'surface of the reflector parabolic on ell parallel horizontal planes and on che interior surface elliptical on ell parallel horizontal planes.y

Fig, 8 shows plan e modiiicetion of my ,condensing reflector in which the exterior all surfe'ce is hyperbolic on zontel planes.

Thev condensing reflector is preferably formed of iwoconlronting` shell like segniente (al, e in Figure 7) Willi its interior surface consisingf of orcs of a series olf downwardly diminishing parallel ellipses Whose nirijor fixes are parallel. and lie on e control vertical glane, :incl whose foci lie on :1 1ferticol line .lFj ll; and its exi/rior surface confsiotingn of a series of correspondingly clin'iinieliing paraboles Whose axes are also parallel and. lie on ille Same central 'vertical plainees the axes olf the ellipses, and whose ioci also lie in the saine vertical line which is olie locus 4el lille foci of elle ellipees. The exterior surface, however7 may lie formeel by e. series of diminishing liyoerliolzis, as indicatori in Figure 8, Wi'li lieir near :foci located on the above nienioned vertical line, :incl their remote lioci rexnoveci 'for lorworll as (licenced by `the length of projected beam cleeired,

y To utilize this .condensing relector most eiectively in combination with niy iii-st mentioned compound reflector, il; is necessary o locale it so time the locus of its foci is coincident with the locus of the foci of the ellipses of'llie lower portion' of .the reflectores described in my cri-pending case end es shown in Figures l and 2 of the drawing, seid locus being 'the vertical line F, FS.

It can be readily seen that; the interior oi this reflector will nncion Whether exilenderl J:from seid "vertical line in e.. lire"- vion oworrl :the lioliJ source, or away from ii, elio results oliteineri depending on ille conics involved. Thal; porlion oil' the rollcotor outward beyond lie fooi, containing "alle if'eriices, and flelineci by n plone pee-sing through the loins rectunle of ille cllipses .parallel lioriond paraboles .Army along ille line opening 'or time inner oroee covered mili will 'le rc einen,

o enriac licini-ellipeoifl, o il lire outer surface olf elle insericzi is linraliolic. llico all cmiv'crging r i' from lli(- inain relecior iinpingrng; thereon `will lie projected mn'irnrilly in parallel relaiion :is nell wlmi now llwy are iriileiy (livergen laterally on emiseion os lltil? irtli consequenlf loe@ in inicnsiry. iliis miler suimice is liyperlzolic Willi ille Ifernole foci al1 a coneiilemble iiielzince, say two or three linnflrcfl fooi. elle inte. S'lwy in crease will be largely the seine, willi ille rays converging to l'l'io remote foci. ,li ille inferior oli rile ielecl'or is cxtenllecl away from the light Source, of course elle interior Surface would have to lie parabolic, instead of elliptical.

The rays from tile main reileclm-7 to elle rear of ilis ininor in., converge on liorizonial planeo., croseina: on ille vertical straight lineoi foci. ll@ FG, ancl mss ourJ through the opening` in time inserted reflector., Similarly to the. rays refleclecl by the interior surface oil the inserted reflector.

vln lling.` l, my condensing reflector A is shown in plan in combination with the main compound lower relier-.tor my copenilinggj cose, and in sido eleve lion in Fig. 2. ln lliio'lat'er position che interior surface onlyT .ltilizerl. onli isy parabolic on all parallel liorizonlel planes 1S in Fig. I prefer, however, to position lie reflector within the nminprojectino' reilecsor. exlenclingr willi its larger opening loir/arci tlie liglii, source l?. while maintaining its focal points on the vertical line of "locus l"--li"'. ne it is shown in l, indicated as is here shown :le parabolic on its exterior snrloce und cllipicnl on in; interior Surface., willi elle locus of ille foci oi all parallel horizontal parabolic and elliptical arcs oeingf the vertical line iSv-47'@ which .is also the locus of the remote foci of all the parallel horizontal eilipicnl orcs in clio nain coinponn projecting reflector and also lire exis of the pencil oi' vertical planeo which will produce parabolic oros on inf/er- Scction with either lie mein projecting rellector or with lle Surface (interior and erior) oi" my conens' isz rciieclior. in F10', l, the reni? coge ./z. of the con ore fer ifo endend l densing reflector is extended back toward 'the' source of light just far enough to 1ntercept all, rays R reflected from the main of both the projectingr reflector and the con- (lensing reflector, Which'axes arccoincidcnt.

'These rays, reflected, are indicated as lt. l The 'interior surface of the condensing reflector iselliptical on all parallel hori- "zontal planes, the light source F being 'at one (the inner) focus common to all the parallel elliptical arcs involved. just as it 1s common to all the elliptical'arcs involved in the co-pending application. The other or remote foci all lie on the vertical line liv-IW, as does also thelocus of r the remote foci of the elliptical arcs in the co-pending case. Thus it will be seen that all direct light from the light source within the angle B, excepting the small portion lost through the opening in the reflector, will' be reflected in parallelism through a vertical plane, and converging on horizontal planes. crossing on the line ot foci liv-FQ. thus reflecting nearly 100% of the spherical candle power used.

If the exterior surface in position A ot the condensingrefiector be changed from parabolic to hyperbolic, as indicated in Fig. 8, the condensing results will be substantiallv Athe same, :for the otl er foci of the hy perbolas could be placed 200 feet. or any distance desired out in front of the lamp.

. Of'course it will be understood that the 'condensingv reflector A can he extended within the main reflector beyond the limit shown in the attached drawings if desired.

If extended beyond the point c shown iu Fig. l', the result-Will he that the exterior surface will intercept raysV reflected from points to the rear of the minor axis m, of the main reflector, and that additional rays from the light source will be intercepted by the interior surface of thel condensing' reflector. vThis may be desirable. as the exterior surface of the reflector will then project in parallelism the more powerful rays vfrein points on the main reflector nearer the light soluce'. and also the interior elliptical surface,k being of relatively small minor axes, will materially reduce the lateral devergence at present given by the main reflector. Y

The lateral spread or the rays produced by the lower portion of the main compound reflector as described in the (io-pending application may be also or further restricted by parting the main reflector on its central vertical longitudinal plane ,and opening the beam aperture the desired amount by pivoting the two halves of the reflector on a vertical axis of rotation. passing through the light source as indicated in Figure 9 of' the drawings.

l clalm:

l. In a headlight having a main reflector and a light source, an auxiliary condensing reflector arranged to receive light from the main reflector at one end and to emit light through the other end, said condensing reflector' being positioned in front of the source of light and having an outer convex reflecting surface and an inner concave reflecting surface, said convex reflecting surface being parabolic on parallel horizontal planes and said concave reflecting surface being elliptical on parallel horizontalplanes. y

2. In a headlight having a main reflector and a light source, an auxiliary condensing reflector arranged to receive light from the main reflector at one end and to emit light through the other end, said condensing reflector being positioned in front of the source of light and having an outer convex reflecting surface and an inner concave refleeting surface, said convex reflecting surface being parabolic on parallel horizontal planes and said concave reflecting surface being elliptical onl parallel horizontal planes and the foci of vtheI'para/llel ellipses and parabolas being on a common locus.

3. In a headlight having a main reflector and a light source, an auxiliary condensing reflector arranged to receive light from the main reflector at one end and to emit light through the other end, said condensing re flector being positioned in 'front of the source of light and having interior and eX- terior reflecting surfaces, the interior sury faces forming in horizontal parallel'sections a series of downwardly diminishing elliptical. arcs., and the exterior surfaces in similar sections a series of downwardly diminishing parabolic arcs. ,l

4. In a structure as defined in claim 3, all the major axes of elliptical and parabolic arcs being parallel on a vertical cen. tral plane and the foci of all the elliptical and parabolic arcs vertically superimposed. 5. ln a headlight having a main reflector and a light source, an auxiliary condensing reflector arranged to receive light from the main reflector at one end and to emit light through the other end, said condensing re- Hector being positioned in front of the source of light and having a reflecting surface whose horizontal parallel sections form a downwardly diminishing series of parabolas with axes parallel on a vertical plane, foci on a vertical line, and vertices on the arc of a parabola.

'in `nmr'izollml .pame sactons a. Swiss mi" downwardly diminishing elliptca MCS, :md the exterior surfas: in smm" sections a series of downwardly diminishing par boli@ :11u35 the foci @f all -the elliptical :sufi parabolic ams 'being vertcaly a-zumrm posed, :md the surface intmwuons z-: either interior o1' exile 'lor sufzma mp u parabolic curves with .n plan@ l'mfmved :zbom the superimposed MARTHA W. @AUSL-mus".

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