US2014429A - Headlamp - Google Patents

Description

Sept. 17, 1.935., R. N. FALGE ET AL '2,014,429

HEADLAM? Filed Feb. 25, 193s s Sheets-sheet 1 @45m 'www Sept. 17, 1935i 'RQ N. FALGE Er AL, 2,014,429

HEADLAMP Filed Feb'. 25, 1933 5 Sheets-Sheet 2 www@ Se'pt. 17, 1935,- R. N. FALGE .ET -AL HEADLAMP Filed Feb. 25, 1935 3 Sheets-Sheet 3 rality of beams of different height.

Patented Sept. 17, 1935 UNITED STATES PATENT OFFICE HEADLAMP Application February 23, 1933, Serial No. 658,058

6 Claims.

This is a continuation in part of our prior application Serial No. 539,518, filed May 23, 1931.

In that application we have set forth a system of illumination for use on automobiles in which each headlamp is capable of projecting a plu- The higher beams are distinguished by the fact that their upper portions are unsymmetrical; that is, the light at the top of the beam is confined to one side of the road. By using at one side of the car a headlamp that projects a beam higher on one side of the road, and on the other side of the car a headlamp that projects a beam higher on the opposite side of the road, it is possible to produce a composite beam that is symmetrical, and similar to the present-day high beam. By depressing the beam from the headlamp that provides the light at the top oi' the left hand side of the beam, a composite beam pattern is obtained which is higher on the right hand side. The driver of an approaching car is consequently relieved of glare, while the high beam on the right hand side gives adequate illumination for passing.r The present application has to do with the design of headlamp used in the system just described.

The design may be embodied either in the reflector, the lens, or in a combination of reflector and lens. We have illustrated all three forms. A characteristic feature of the invention consists in so forming the reflector, lens, or both, that the areas that provide light at the top of the beam are formed to throw light to one side of the road, While the remaining areas are formed to spread the light more or less across the width of the road as desired to give good general illumination. In the case of headlamps capable of providing beams of different height in accordance with present practice, it is the intermediate Zone of the lamp that provides the top light, and hence it is this region that is shaped to throw light to one side of the road. This may be done by either providing the lens with half flutes, or with side bending prisms and full flutes which are optically the same thing, or by bending the corresponding portion of the refiector so as to throw the light to one side. 'I'hisis most conveniently -done by properly fluting the reflector.

In the accompanying drawings:

Figure l is a vertical section through our improved headlamp embodying a special reflector for producing a drop in the beam.

Figure 2 is a front View of the lens employed in the lamp of Figure l.

Figure 3 is a section on line 3 3 of Figure 2.

Figure iis a section on line A-A of Figure 2,

(Cl. 24d-41,25)

showing the arrangement of flutes over the corresponding portion of the lens in the case of the right headlamp, while Figure 5 is a section taken on the same line showing the arrangement of flutes in the case of the left headlamp.

Figure 6 is a vertical section through a modified form of our headlamp.

Figure 7 is a front view of the lens shown in Figure 6.

Figure 8 is a front view of a special reflector which may be used instead of the lens and reflector combinations previously described.

Figure 9 is a section on line 9-9 of Figure 8.

Figure 10 is a section on line lil- IB of Figure 8.

Figures 11, i2 and 13 show the beam patterns 15 produced by the left headlamp made according to our invention.

A headlamp consists essentially of a light source and light directing means which may consist either of a reflector alone, or of a combination of 20 reflector and lens. In addition, headlamps have been developed in which light is directed by the lens alone, but such designs have so far not found wide application in automobile headlights.

In Figures l to 5 we have disclosed a headlamp in which the light is directed by means of a special reflector, and a special lens; in Figures 6 and 7 we have shown a headlamp in which light is directed by a plain parabolic reflector and a special lens, and in Figures S to l0` we have shown a 30 special reflector which directs the light where desired without the use of a lens. Each of the light directing devices shown in Figures 1, 6 and 8 divided into three transversely extending superimposed zones or areas, the upper and 35 lower Zones of which are constructed to depress light downwardly. In each form of the invention the top zone is numbered l, the intermediate Zone is numbered 2, and the lower Zone is numbered 3. In Figures 1 and 8 the light from zones 40 i and 3 is bent downwardly by tilting the corresponding portions of the reector as indicated by the tilted axis |-l'. In Figure 6 thesame result is achieved by using down-bending prisms it on the upper zone I, and down-bending prisms 3Q on the lower zone 3.

To secure insensitivity to variations of the light sources from their proper positions vertically, the intermediate zone 2 is given special treatment to throw the light from the center portion 4 toward 50 l the bottom of the beam so that the top of the beam is formed by the light coming from the sides of the intermediate Zone which are numbered 5, In the forms of our invention shown in Figures 1 and 8 this is accomplished by axially offsetting 554 the upper and lower halves of the reflector, thus the upper half will have its focus at F, while the lower half will have its focus at F2. If preferred a similar result may be obtained by tilting the center of the intermediate zone downwardly with respect tothe sides as disclosed in the prior patent to Brown, 1,822,839, granted September 8, 1931. It will be understood that the phrase substantially parabolic reflector as used in the claims includes reflectors having the modifications just described as well as plain parabolic reectors. In the form of our invention shown in Figure 6, this result is accomplished byproviding the center of the lens with down-bending prisms 20, which, however, are of less bending power .than the prisms l0 or 39. If desired, the sides ofthe central Zone may be equipped with lighter downbending prisms in accordance with present practice.

The light source we employ is an incandescent lamp, and while Vthere may be considerable variation in rthe design of filaments, we prefer to employ filaments of Yconventional V-shape, one numbered 8 between the foci of the reflector, another, numbered l2', `approximately g above the focus, and a third, ynumbered 14', approximately l below the focus. However, the only essential thing is that there be light sources in the reflector spaced vertically from each other with or `without `lateral displacement. The only effect of Vlateral displacement is to give a slight sidewise shift to the beam as disclosed in the prior patent to Sumner E. Brown No. 1,792,806.

The .construction so far described will provide three symmetricalbeams the highest beam being projected from the lament i4', the next highest from the filament 8', and the lowest from the lament I2'. .The beams produced from the last two filaments will correspond with the present day high beam and low beam, respectively, while the beam produced by the lowest filament I4 will provide a beam higher than any now permitted in most States, but `one vwhich gives excellent illumination for driving over rolling and hilly roads.

, To provide va beam with an asymmetrical top we `have formed Vthe reflector or the lens so as to direct the light from the intermediate zone toward one side of the road. This may be accomplished by properly shaping the corresponding part .of vthe lens as illustrated in Figures 4 and 5. In Figure 4 we have illustrated fractional flutes designed .to throw light toward the left side of the road. As explained in our prior application, half flutes consist essentially of side-bending prisms provided with full flutes to spread the light in the amount desired. The right hand headlamp will preferably be `provided with half flutes as shown in Figure 4 to direct light to the left of the road, while the left headlamp will be provided with half lflutesas shown in Figure 5 to directlight to the right vof the road. If desired, the half flutes may be designed for lateral insensitivity as described in our first filed application; that is, in the casefof the left hand headlamp the left boundary of the asymmetrical portion of the beams may be provided by rays from the extreme side portions of the reflector, these portions f being less `sensitive to lateral displacement of the light source. The flutes over these portions of. the reector are Idesigned with little or no prismatic action at their left extremities. The `prismatic action ,at the left side ofthe half flutes increases as the vertical center line of the lamp is approached. As a consequence, going from the side of the lampto the centerline, the left-most ray V.the reiiector shown in Figure 8 by the provision 'of half flutes formed in the intermediate section of the refiector itself as illustrated in Figure 9.

The light from the top and bottom sections I anelli is spread across the width of the roadway by the use of full flutes either on the lens as shown in Figures v2 and 3, or on the reflector as shown in Figures 8 and 10.

Obviously, if preferred, hybrid types may be employed, for example, full flutes may be used on the intermediate section of the binationwith side-bending prisms on the lens, or the reverse arrangement may be used, that `is, the yintermediate section o'f the reflector Vmay `be turnedto throw light toone'side of the road, and the light may be spread lby the provision of "full flutes on the lens. @ther obvious combinations will occur to Athose skilled in the-art. l

`rIhe beam patterns produced by the left headlamp of each of theforms of the invention illustrated are shown iin Figures `11 to y1-3, these patterns `being appropriately labeled iso that no Afurther description Vis necessary. The beam patterns of the right lamps wil-l be -of vthe same design except that the Aasymmetrical vportion will be on the opposite side of the 'road-in other words as if one were looking at the "pattern through the paper.

Many modifications of our invention will beobvious. For example, so long as the bulk of the rays of each section are directed in t-he Vmanner described, an occasional area Ain the intermediate Zone may be 'provided 'with a full -iiute `or flutes, oran occasional area in Vthe top andfbottom zone maybe provided with a half flute or flutes without sensibly altering I`the optical result, for such expedients are now and then necessary 'to smooth up the beam.

v'lhe degree `of spread -of `the `light from any of the sections imay fbe varied as desired, Vand for some 'purposes "it may Vbe lthat little or no. spread will 'be needed. Various `designs and arrangements of filaments may be employed to alter the depth or shift of the beams. However, We have described what we vbelieve to vbe a superior arrangement.

Instead of doing Iall ofthe downward bending in the reflector or lens part may be done in the reiiector and part in the lens. The same is `true in the case of the sidewise bending or spreading of the.l light. `If preferred, convex flutes may be employed instead of concave flutes and in such event the same principle of design would be employed to render them insensitive to variations in lateral position. It is likewise lobvious that instead of using -a num-ber of Afilaments-one light source may be shifted fto the various positions in the refector.

While we have illustrated a `construction in which the left lamp provides the light at the top right hand side of the beam and the right lamp provides the light .at `the top left hand side of the beam, it is not essential that the beams v'from the two lamps be thus criss-crossed. If preferred the right lamp may :provide the light at the 'top of the `beam onl its :side of d;he.road, 4and the left reector in, comlamp may provide the light at the top of the beam on its side of the road. However, it is important that the lamp which provides light at the top right hand side of the beam shall not direct light in any quantity into the top left side of the high beam, otherwise an asymmetric beam will not be obtained when the beam from the other lamp is dropped. In the case of the lamp which projects light to form the upper left hand p-ortion of the high beam, it is only essential that all of the rays going into that portion of the beam shall be dropped upon going to the lower beam.

We claim:

1. A lens for use in depressible beam headlighting systems for automobiles provided with three transversely extending superimposed zones, the central zone being provided with unsymmetrical iiutes, for directing light to one side of the road in the form of a laterally elongated beam, while the top and bottom Zones are provided with flutes for projecting light across the Width of the road.

2. A headlamp comprising light projecting eans including a substantially parabolic reflector and a glass closure, means providing a source of light adjacent the focal region of the reflector, said light projecting means being subdivided into upper, intermediate and lower transversely extending superimposed Zones, said intermediate zone being provided with means for directing substantially all of the light to one side of the road in the form of a laterally elongated beam, one of the zones other than the intermediate zone being provided with means for directing light across the full width of the road, said upper and lower Zones being formed to direct the rays falling upon them beneath the rays from the intermediate zone.

3. A headlamp comprising light projecting means including a substantially parabolic reflector and a glass closure, means providing a source of light adjacent the focal region of the reflector, said light projecting means being subdivided into upper, intermediate and lower transversely extending superimposed zones, said intermediate Zone being provided with means for directing substantially all of the light to one side of the road in the form of a laterally elongated beam while the upper and lower zones are provided with means for directing light across the full width of the r-oad, said upper and lower Zones being formed to direct the rays falling upon them beneath the rays from the intermediate zone.

4. A headlamp comprising light projecting means including a substantially parabolic reflector and a glass closure, means providing a source of light adjacent the focal region of the reflector or at a point above the focal region, said light projecting means being subdivided into upper, intermediate and lower transversely extending superimposed Zones, the rays of light from said upper and lower zones being but slightly affected by shifting from one source to the other while the rays of light from said interme' diate Zone are shifted sharply downwardly upon energizing the upper source, said intermediate zone being provided with means for spreading substantially all of the light to one side of the road in the form of a laterally elongated beam,

one of the zones other than the intermediate Zone being provided with means for spreading light across the full width of the road, said upper and lower Zones being formed to direct the rays falling upon them beneath the top of the beam produced when the lower source is energized, whereby, upon changing to the upper source, an effective lowering of the top of the high side of the beam is secured.

5. A headlamp comprising light projecting means including a substantially parabolic reector and a glass closure, means providing a source of light adjacent the focal regio-n of the reflector or at a point above the focal region, said light projecting means being subdivided into upper, intermediate and lower transversely extending superimposed Zones, the rays of light from said upper and lower Zones being but slightly affected by shifting from one source to the other while the rays of light from said intermediate Zone are shifted sharply downwardly upon energizing the upper source, the intermediate zone being provided with means for directing substantially all of the light to one side of the road in the form of a laterally elongated beam while the upper and lower zones are provided with means for directing light across the full width of the road, said upper and lower Zones being formed to direct the rays falling upon them beneath the top of the beam produced when the lower source is energized, whereby, upon changing to the upper source, an eiective lowering of the top of the high side of the beam is secured.

6. A lens as dened in claim l having the last named zones provided with down-bending prisms.

ROBERT N. FALGE. CHARLES E. GODLEY.

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